Announcement

**Giuseppe** · January 7, 2011, 11:07 AM

EuroFlu - Weekly Electronic Bulletin - Week 52 : 27/12/2010-02/01/2011 - 07 January 2011, Issue N? 383 (Extract, edited)

EuroFlu - Weekly Electronic Bulletin - Week 52 : 27/12/2010-02/01/2011 - 07 January 2011, Issue N? 383 (Extract, edited)

[Source: EuroFlu, full page: <cite cite="http://www.euroflu.org/cgi-files/bulletin_v2.cgi">EuroFlu - Bulletin Review</cite>. Extract, edited.]

EuroFlu - Weekly Electronic Bulletin - Week 52 : 27/12/2010-02/01/2011 - 07 January 2011, Issue N? 383

Increasing influenza activity with highest intensity in western Europe

This issue is based on data reported in week 52/2010 by 39 Member States in the WHO European Region.
Influenza activity increased, particularly in western countries.
45% of sentinel specimens tested positive for influenza.
Pandemic influenza A(H1N1) 2009, influenza B and influenza A(H3N2) viruses are circulating in the Region.

Current situation - week 52/2010

Increasing consultation rates were reported by 12 of the 32 countries submitting data on influenza-like illness (ILI) and/or acute respiratory infection (ARI), mostly in children aged 0-4 years.

In the United Kingdom (England), the group aged 5-14 was most affected.

Of the 10 countries presenting calculated baseline thresholds, 5 (France, Ireland, Israel, Luxembourg and Ukraine) reported clinical consultation rates above the thresholds.

Denmark and the United Kingdom (England) reported a high intensity of influenza activity.

Of the 38 countries reporting on the geographical spread of influenza, 11 reported widespread activity; 5 reported regional activity; 6 reported local activity and the remaining 16 reported no or sporadic activity.

The impact of influenza on health care systems was low in 16 of the 21 countries reporting on this indicator, with Ireland, Israel, the United Kingdom (Wales and Scotland) and Turkey reporting moderate impact.

In the United Kingdom, the picture of the illness associated with influenza A(H1N1)2009 infection is consistent with that seen in the 2009 pandemic, with a similar demographic impact: particularly affecting children and young adults.

The virological picture is complex, with many strains of influenza virus circulating but no antigenic change in the influenza A(H1N1) 2009 virus, and no immediately obvious genetic differences between viruses recovered from fatal cases and those causing mild illness.

See a Eurosurveillance article for more information.

Virological situation - week 52/2010

Sentinel physicians collected 1072 respiratory specimens, of which 479 (45%) were positive for influenza virus: 370 (77%) were influenza A and 109 (23%) were influenza B.

Of the influenza A viruses, 307 were subtyped: 262 (85%) as pandemic A(H1) and 45 (15%) as A(H3).

For the 13 countries testing 20 or more sentinel specimens, influenza positivity ranged from 3% to 81%, with a median of 44% (mean: 47%).

Influenza positivity was highest in the United Kingdom (Scotland) (81%), Belgium (77%), Switzerland (59%), Israel (56%) and Spain (54%).

Among specimens tested from non-sentinel sources, 2865 were positive for influenza: 2055 (72%) influenza A and 810 (28%) were influenza B.

Of the influenza A viruses, 971 were subtyped: 965 (99%) as pandemic A(H1) and 6 (1%) as A(H3).

Respiratory syncytial virus continued to be detected.

Since week 40/2010, 238 influenza viruses had been characterized antigenically: 101 were A(H1) pandemic A/California/7/2009 (H1N1)-like; 42 were A(H3) A/Perth/16/2009 (H3N2)-like; 6 were B/Florida/4/2006-like (B/Yamagata/16/88 lineage), and 89 were B/Brisbane/60/2008-like (B/Victoria/2/87 lineage).

Based on the genetic characterization of 42 influenza viruses, 30 belonged to the pandemic A/California/7/2009 A(H1N1) clade; 3 belonged to the A(H3) clade represented by A/Perth/16/2009; 4 belonged to the subgroup represented by A/Hong Kong/2121/2010 in the A/Victoria/208/2009 A(H3) clade; 4 belonged to the B/Bangladesh/3333/2007 clade (Yamagata) lineage; and 1 to the B/Florida/4/2006 clade (Yamagata) lineage.

Cumulative virological update - weeks 40-52/2010

A total of 9204 influenza virus detections were reported, of which 6500 (71%) were influenza A and 2704 (29%) influenza B.

Of the influenza A viruses, 3593 were subtyped: 3285 (91%) as pandemic influenza A(H1), 307 (9%) as influenza A(H3) and 1 (less than 1%) as influenza A(H1).

Comment

Influenza activity has increased, with the highest intensity of circulation in countries of western Europe. Widespread activity was reported by Belgium, Denmark, Ireland, Israel, France, the Netherlands, Norway, Portugal, Switzerland and the United Kingdom (England and Wales).

Overall, influenza activity remains low in other countries in the WHO European Region.

Owing to the holidays, few countries in the eastern part of the Region reported data to EuroFlu.

In week 52/2010, 45% of sentinel samples tested positive for influenza, compared with 34% and 39% in the previous two weeks.

Pandemic A(H1N1) 2009, influenza B and influenza A(H3) viruses were co-circulating in the Region, with pandemic A(H1N1) 2009 being dominant in 11 countries, influenza A and B being co-dominant in 4 countries and influenza type B dominating in 4 countries.

The WHO Regional Office for Europe continues to monitor the situation concerning severe influenza cases closely.

Member States are advised to follow current WHO recommendations, for more information click here.

Further information

The EuroFlu bulletin describes and comments on influenza activity in the 53 countries in the WHO European Region. Further information can be obtained from the web sites of WHO/Europe, WHO headquarters and the European Centre for Disease Prevention and Control.

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Network comments (where available)

England
- Due to bank holidays in week 52 (ending 2 January) GP surgeries were only open for three days, which will have impacted GP consultation rates so data should be interpreted cautiously. A similar 'dip' in consultation rates is often seen at this time of year.
Malta
- Situation stable
Scotland
- Increasing number of SARI cases
- Increasing number of SARI cases attributable to Influenza A H1N1 (2009 strain)

(...)
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**Giuseppe** · January 7, 2011, 11:48 AM

Weekly influenza surveillance overview - 7 January 2011 (ECDC, extract, edited)

Weekly influenza surveillance overview - 7 January 2011 (ECDC, extract, edited)

[Source: European Centre for Disease Prevention and Control, full PDF document (LINK). Extract, edited.]

SURVEILLANCE REPORT

Weekly influenza surveillance overview - 7 January 2011

Main surveillance developments in week 52/2010 (27 Dec 2010 ? 02 Jan 2011)

This first page contains the main developments of this week and can be printed separately or together with the more detailed information following.

Generally, reporting of influenza has been less complete over weeks 51 and 52 due to the holiday period, which reduces consulting rates and reporting to national centres and subsequently onto ECDC.
Nevertheless, in week 52/2010, 15 of the 25 countries reported increasing trends of influenza activity.
After little change in week 51/2010, the percentage of sentinel specimens that tested positive for influenza rose to 46% in week 52/2010, indicating rising intensity.
For combined sentinel and non-sentinel influenza positive specimens, 73% were type A and 27% were type B.
Ninety-eight percent of sub-typed influenza A viruses were A(H1N1) 2009.
In week 52/2010 six countries reported 56 SARI cases, of which 22 were known to have been infected by the A(H1N1) 2009 virus.
Of the 613 SARI cases reported since week 40/2010, twelve deaths have been reported.

Sentinel surveillance of influenza-like illness (ILI)/ acute respiratory infection (ARI):

High or medium influenza activity was reported by 11 countries and widespread activity was reported by eight countries. Increasing trends of influenza activity were reported by 15 countries.

Virological surveillance:

In week 52/2010, an increased percentage (46%) of sentinel specimens tested positive for influenza compared with week 51/2010. Of the 7854 combined sentinel and non-sentinel influenza positive specimens gathered in week 52/2010, 73% were type A and 27% were type B.

Hospital surveillance of severe acute respiratory infection (SARI):

In week 52/2010, six countries reported 56 SARI cases, of which 22 tested positive for the A(H1N1) 2009 infection. Three additional countries provided comments relating to the hospital care and the impact of the influenza cases on services.

Sentinel surveillance (ILI/ARI) - Weekly analysis ? epidemiology

During week 52/2010, medium influenza activity was reported by Belgium, France, Italy, Luxembourg, Malta, Norway, Portugal, Spain and the UK (Northern Ireland, Scotland and Wales). Denmark, Ireland and the UK (England) reported high intensity. Fourteen countries experienced low intensity influenza activity (Table 1, Map 1).

Widespread activity was reported by seven countries and the UK (England and Wales). Regional activity was reported by Finland, Italy, Luxembourg and Spain and local activity by Germany, Malta and the UK (Northern Ireland and Scotland). Sporadic activity was reported by nine countries, and two countries (Austria and Bulgaria) reported no activity (Table 1, Map 2).

Compared with the previous week, a greater number of countries?six in week 51 and 15, including the UK (Northern Ireland, Wales and Scotland), in week 52?reported increasing trends for their clinical activity (Table 1, Map 2).

(...)

Table 1: Epidemiological and virological overview by country, week 52/2010

[Country - Intensity - Geographic spread - Trend - No. of sentinel swabs - Dominant type - Percentage positive* - ILI per 100.000 - ARI per 100.000]

Austria - Low - No activity - No information available - 7 - None - 42.9 - ... - 7.2
Belgium - Medium - Widespread - Stable - 30 - A, B - 76.7 - 252.8 - 1543.8
Bulgaria - Low - No activity - Decreasing - ... - None - 0.0 - ... - 666.9
Cyprus - ... - ... - ... - ... - ... - 0.0 - ... - ...
Czech Republic - Low - Sporadic - Stable - 7 - None - 14.3 - 18.1 - 673.1
Denmark - High - Widespread - Increasing - 15 - None - 40.0 - 121.4 - ...
Estonia - Low - Sporadic - Stable - 15 - None - 20.0 - 6.6 - 332.0
Finland - No information available - Regional - Stable - 29 - A(H1N1) 2009 - 37.9 - ... - ...
France - Medium - Widespread - Increasing - 137 - None - 43.1 - ... - 2426.7
Germany - Low - Local - Increasing - 37 - A(H1N1) 2009 - 43.2 - ... - 950.3
Greece - Low - Sporadic - Increasing - 1 - A(H1N1) 2009 - 0.0 -123.1 - ...
Hungary - Low - Sporadic - Decreasing - 31 - ... - 3.2 - 66.0 - ...
Iceland - Low - Sporadic - Increasing - 18 - ... - 11.1 - 4.1 - ...
Ireland - High - Widespread - Increasing - 0 - A(H1N1) 2009 - 0.0 - 120.6 - ...
Italy - Medium - Regional - Increasing - 39 - A(H1N1) 2009 - 30.8 - 378.6 - ...
Latvia - Low - Sporadic - Stable - 0 - A(H1N1) 2009 - 0.0 - 0.0 - 778.0
Lithuania - Low - Sporadic - Increasing - ... - ... - 0.0 - 11.7 - 479.8
Luxembourg - Medium - Regional - Increasing - 31 - A(H1N1) 2009/B - 51.6 - ...* - ...*
Malta - Medium - Local - Increasing - ... - ... - 0.0 - ...* - ...*
Netherlands - Low - Widespread - Stable - 17 - ... - 64.7 - 36.4 - ...
Norway - Medium - Widespread - Increasing - 8 - B - 62.5 - 60.1 - ...
Poland - Low - Sporadic - Increasing - 5 - None - 40.0 - 65.1 - ...
Portugal - Medium - Widespread - Increasing - 5 - B - 40.0 - 75.2 - ...
Romania - Low - No activity - Decreasing - 19 - None - 10.5 - 13.6 - 591.3
Slovakia - ... - ... - ... - 1 - None - 0.0 - ... - ...
Slovenia - Low - Sporadic - Stable - 23 - A(H1N1) 2009 - 43.5 - 15.9 - 1333.2
Spain - Medium - Regional - Increasing - 259 - A(H1N1) 2009 - 53.7 - 152.2 - ...
Sweden - ... - ... - ... - ... - ... - 0.0 - ... - ...
UK - England - High - Widespread - Stable - 0 - A, B - 0.0 - 98.4 - 598.9
UK - Northern Ireland - Medium - Local - Increasing - 3 - A(H1N1) 2009 - 66.7 - 179.5 - 461.7
UK - Scotland - Medium - Local - Increasing - 32 - A(H1N1) 2009 - 81.3 - 20.3 - 234.5
UK - Wales - Medium - Widespread - Increasing - ... - ... - 0.0 - 89.2 - ...
Europe - ... - ... - ... - 769 - ... - 45.8 - ... - ...

(*) Incidence per 100 000 is not calculated for these countries as no population denominator is provided.

Note: Liechtenstein is not reporting to the European Influenza Surveillance Network

Description of the system

This surveillance is based on nationally organized sentinel networks of physicians, mostly general practitioners (GPs), covering at least 1?5% of the population in their countries. All EU/EEA Member States (except Liechtenstein) are participating. Depending on their country?s choice, each sentinel physician reports the weekly number of patients seen with influenza-like illness (ILI), acute respiratory infection (ARI) or both to a national focal point. From the national level, both numerator and denominator data are then reported to the European Surveillance System (TESSy) database. Additional semi-quantitative indicators of intensity, geographic spread and trend of influenza activity at the national level are also reported.

Virological surveillance - Weekly analysis ? virology

In week 52/2010, virological data were reported by 24 countries and the UK (Northern Ireland and Scotland). Sentinel physicians collected 769 swabs with an increased percentage (45.8 %) testing positive for influenza virus compared with the previous week (33.5%) (Tables 1 and 2, Figure 3).

In addition, 2404 non-sentinel source specimens (i.e. specimens collected for diagnostic purpose in hospitals) were reported positive for influenza virus.

Compared with the previous week, the number of specimens positive for influenza decreased in sentinel practices and increased in non-sentinel sources.

This divergence might be explained by differences in reporting in both systems during holidays.

Of the 2756 influenza viruses detected during week 52/2010, 2093 (76%) were type A and 663 (24%) were type B. The latter virus was reported as dominant in Norway and Portugal (Table 1). Of the 992 influenza A viruses that were sub-typed, 976 (98.4%) were A(H1N1) 2009 and 16 (1.6%) were A(H3) virus (Table 2).

Since week 40/2010, of the 7854 influenza detections in sentinel and non-sentinel specimens, 5764 (73%) were influenza A and 2090 (27%) influenza B viruses. Of 2959 influenza A viruses sub-typed, 2830 (95.6%) were A(H1N1) 2009 and 129 (4.4%) were A(H3) viruses (Table 2). Trends of virological detections since week 40/2010 are shown in Figures 1?3.

Since week 40/2010, 236 influenza viruses from sentinel and non-sentinel specimens have been characterised antigenically (Table 3): 99 as A/California/7/2009 (H1N1)-like; 42 as A(H3)/Perth/16/2009 (H3N2)-like; 89 as B/Brisbane/60/2008-like (Victoria lineage); and six as B/Florida/4/2006-like (Yamagata lineage) (Figure 4).

More details on circulating viruses can be found in the report prepared by the Community Network of Reference Laboratories coordination team. Also, a detailed analysis of the viruses isolated in the UK was published this week in Eurosurveillance indicating no evidence of any change in the A(H1N1)2009 or B viruses in that country and a good match with the seasonal vaccine.

In week 52/2010, there was a decrease in respiratory syncytial virus detections, but it may be premature to conclude that the circulation of the virus is declining (Figure 5).

Table 2: Weekly and cumulative influenza virus detections by type, subtype and surveillance system, weeks 40/2010?52/2010

[Virus Type/Subtype - Current Period: Sentinel - Non-Sentinel / Season: Sentinel - Non-sentinel]

Influenza A - 280 - 1813 / 1411 - 4353
- A H1N1 (2009) - 209 - 767 / 1208 - 1622
- A (subtyping not performed) - 61 - 1040 / 132 - 2673
- A (not subtypable) - 0 - 0 / 0 - 0
- A (H3) - 10 - 6 / 71 - 58
- A (H1) - 0 - 0 / 0 - 0
Influenza B - 72 - 591 / 565 - 1525
Total Influenza - 352 - 2404 / 1976 - 5878

Note: A(pandemic H1), A(H3) and A(H1) includes both N-subtyped and not N-subtyped viruses

(...)

Description of the system

According to the nationally defined sampling strategy, sentinel physicians take nasal or pharyngeal swabs from patients with influenza-like illness (ILI), acute respiratory infection (ARI) or both and send the specimens to influenza-specific reference laboratories for virus detection, (sub-)typing, antigenic or genetic characterisation and antiviral susceptibility testing.

For details on the current virus strains recommended by WHO for vaccine preparation, click here.

Hospital surveillance ? severe acute - respiratory infection (SARI)

Weekly analysis ? SARI

During week 52/2010, 56 SARI cases were reported by six countries (Table 3). Only three countries?Belgium, Romania and Slovakia?were collecting syndromic sari cases; the remainder of the countries are still reporting only influenza confirmed hospitalised cases or severe influenza cases admitted to ICU, as in France.

Three cases were reported by Austria; 19 by Belgium; 16 by Spain; six by France; four by Portugal; and eight by Romania. Of the 26 cases that tested positive for influenza, 22 were infected by A(H1N1) 2009, three by an influenza A virus (not further sub-typed) and one by a B virus. Portugal, Spain and Romania each reported one fatality; the fatality in Portugal was associated with A(H1N1) 2009 virus infection, the one in Spain with influenza A infection (sub-type unknown) and no influenza virus was detected in the fatality reported by Romania. Since week 40/2010, 12 deaths were recorded among reported SARI cases.

In addition, comments on SARI cases were sent by three countries (see country comments).

Table 3: Cumulative number of SARI cases, week 40/2010?week 52/2010

[Country - Number of cases - Incidence of SARI cases per 100,000 population - Number of fatal cases reported - Incidence of fatal cases per 100,000 population - Estimated population
covered]

Austria - 3 - ... - ... - ... - ...
Belgium - 407 - ... - ... - ... - ...
Spain - 88 - ... - 3 - ... - ...
France - 17 - ... - 1 - ... - ...
Portugal - 17 - ... - 4 - ... - ...
Romania - 79 - 1.23 - 4 - 0.06 - 6.413.821
Slovakia - 2 - ... - ... - ... - ...
Total - 613 - ... - 12 - ... - ...

(...)

Table 4: Number of SARI cases by age and gender, week 52/2010

[Age groups - Male - Female - Unknown]

Under 2 - 8 - 6 - ...
2-17 - 8 - 5 - ...
18-44 - 8 - 3 - ...
45-59 - 8 - 6 - ...
>=60 - 3 - 1 - ...
Total - 35 - 21 - ...

Table 5: Number of SARI cases by influenza type and subtype, week 52/2010

[Virus type/subtype - Number of cases during current week - Cumulative number of cases since the start of the season]

Influenza A - 25 - 121
- A (pandemic H1N1) - 22 - 96
- A(subtyping not performed) - 3 - 12
- A(H3) - ... - 2
- A(H1) - ... - 11
- A(H5) - ... - ...
Influenza B - 1 - 6
Unknown - 30 - 482
Total - 56 - 637

Table 6: Number of SARI cases by antiviral treatment, week 52/2010

[Antiviral treatment - Number of patients who received prophylaxis - Number of patients who
received anti-viral treatment]

Oseltamivir - 1 - 87
Zanamivir - ... - 3
Other (or combinations with other) - 1 - 2
Unknown - 512 - 455
None - 99 - 66
Total - 613 - 613

Table 7: Number of SARI cases by level of care and respiratory support, week 52/2010

[Respiratory support - ICU - Inpatient ward - Other - Unknown]

No respiratory support necessary - 14 - 17 - 203 - ...
Oxygen therapy - 32 - 38 - 162 - ...
Ventilator - 46 - 2 - 5 - 1
Respiratory support given unknown - 38 - 1 - 34 - 20

Table 8: Number of SARI cases by vaccination status, week 52/2010

[Vaccination Status - Number Of Cases - Percentage of cases]

Seasonal 2010 vaccination - 1 - 2
Unknown - 25 - 44.6
TOTAL - 613 - ...

(...)

Table 9: Number of underlying conditions in SARI cases by age group, week 52/2010

[Underlying condition/risk factor - 0-11 months - 1-4 years - 5y-14 - 15-24 - 25-64 - >=65]

Asthma - ... - 1 - 1 - ... - 1 - ...
Diabetes - ... - ... - ... - ... - 5 - 2
Chronic heart disease - 3 - ... - ... - ... - 11 - 7
Chronic lung disease - 1 - 1 - ... - 1 - 7 - 1
Pregnancy - ... - ... - ... - 3 - 5 - ...
Underlying condition unknown - 1 - 3 - 1 - 4 - 43 - 2
Other (including all other conditions) - 164 - 121 - 40 - 4 - 110 - 69

Note: The data is collected for asthma, cancer, diabetes, chronic heart disease, HIV/other immune deficiency, kidney-related conditions, liver-related conditions, chronic lung disease, neurocognitive disorder (including seizure), neuromuscular disorder, obesity (BMI between 30 and 40), morbid obesity (BMI above 40), pregnancy, other, underlying condition unknown and for no underlying condition.

Country comments

In addition, comments on SARI cases and the impact on hospital services were sent by the following:

Czech Republic:
- Two SARI cases?a 54-year-old male with no risk condition and 41-year-old female with moderate asthma?with laboratory confirmed influenza A(H1N1) 2009 virus and both with bilateral pneumonia were reported.
Denmark:
- Since week 49/2010, a total of 12 influenza patients have been reported by intensive care units (ICUs) in Denmark: four women and eight men. The median age was 52 years (range 15?70 years). Nine patients had influenza A, six of whom were further typed and had subtype A(H1N1) 2009. Two patients had influenza B.
- Four patients were previously healthy people: a 59-year-old male, a 30 year?old female, a 22-year-old male and a 15?year-old girl.
- For eight patients, one or more underlying illnesses were reported. Chronic obstructive lung disease, hypertension and chronic lymphatic leukemia were each mentioned twice. Other underlying illnesses included Wegener?s granulomatosis, obesity, alcoholism, kidney failure and asthma.
- There were no pregnant women among the 12 patients.
- Two patients were receiving extracorporeal membrane oxygenation treatment (ECMO).
UK (England):
- Due to bank holidays in week 52/2010, general practitioner (GP) surgeries were only open for three days, which will have impacted GP consultation rates, so data should be interpreted cautiously.
- A similar dip in consultation rates is often seen at this time of year.
- The following is a list of the number of patients in England with confirmed or suspected influenza in critical care beds by age of patient:
  - Week ending 15 Dec 2010:
    - <5=10;
    - 5-15=9;
    - 16-64=141;
    - 65+=22.
    - Total=182;
  - Week ending 23 Dec 2010:
    - <5=26;
    - 5-15=17;
    - 16-64=366;
    - 65+=51.
    - Total=460;
  - Week ending 30 Dec 2010:
    - <5=42;
    - 5-15=24;
    - 16-64=586;
    - 65+=86.
    - Total=738;
  - Week ending 6 Jan 2010:
    - <5=30;
    - 5-15=17;
    - 16-64=640;
    - 65+=96.
    - Total=783.
- The overall number of severely ill patients with confirmed or suspected flu in critical care has continued to rise. As of 06 January 2011, there were 783 patients with confirmed or suspected influenza in NHS critical care beds in England. These patients occupied 22.5 % of available critical care beds nationally.
- For further information, click here (LINK)
UK (Scotland):
- Increasing number of SARI cases attributable to influenza A H1N1 (2009 strain).

The report text was written by an editorial team at the European Centre for Disease Prevention and Control (ECDC): Eeva Broberg, Flaviu Plata, Phillip Zucs and Ren? Snacken. The bulletin text was reviewed by the Community Network of Reference Laboratories for Human Influenza in Europe (CNRL) coordination team: Adam Meijer, Rod Daniels, John McCauley and Maria Zambon. On behalf of the EISN members the bulletin text was reviewed by Bianca Snijders (RIVM Bilthoven, The Netherlands) and Thedi Ziegler (National Institute for Health and Welfare, Finland)

Maps and commentary used in this Weekly Influenza Surveillance Overview (WISO) do not imply any opinions whatsoever of ECDC or its partners on the legal status of the countries and territories shown or concerning their borders.

All data published in the WISO are up-to-date on the day of publication. Past this date, however, published data should not be used for longitudinal comparisons as countries tend to retrospectively update their numbers in the database.

? European Centre for Disease Prevention and Control, Stockholm, 2010

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**Giuseppe** · January 12, 2011, 11:17 AM

EuroFlu - Influenza-like Illness Activity - Geographical Spread Indicator - Snapshot, January 12 2011

Source: EuroFlu.org, Interactive Maps page: http://www.euroflu.org/html/maps.html

EuroFlu - Influenza-like Illness Activity - Geographical Spread Indicator - Snapshot, January 12 2011

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Attached Files

**Giuseppe** · January 14, 2011, 10:48 AM

EuroFlu - Weekly Electronic Bulletin - Week 1 : 03/01/2011-09/01/2011 - 14 January 2011, Issue N? 384 (Extract, edited): Some countries are experiencing strains on critical care capacities.

EuroFlu - Weekly Electronic Bulletin - Week 1 : 03/01/2011-09/01/2011 - 14 January 2011, Issue N? 384 (Extract, edited)

[Source: EuroFlu, full page: <cite cite="http://www.euroflu.org/cgi-files/bulletin_v2.cgi">EuroFlu - Bulletin Review</cite>. Extract, edited.]

EuroFlu - Weekly Electronic Bulletin - Week 1 : 03/01/2011-09/01/2011 - 14 January 2011, Issue N? 384

Widespread influenza activity in countries of northern and western Europe

This issue is based on data reported in week 01/2011 by 47 Member States in the WHO European Region.
Influenza activity is increasing in north-western Europe.
44% of sentinel specimens tested positive for influenza.
Pandemic influenza A(H1N1) 2009 and influenza B are the predominant viruses circulating in the Region with relatively few influenza A(H3N2) viruses being detected.
Some countries are experiencing strains on critical care capacities due to patients with severe disease caused by influenza (see Network comments).

Current situation - week 01/2011

Consultation rates for influenza-like illness (ILI) and acute respiratory infection (ARI) increased in 20 out of 41 countries that reported on this indicator. The age groups affected varied between countries, but in about half the countries increases were seen in all age groups.

Of the 10 countries that present a baseline, 6 reported clinical consultation rates above the national threshold (France, Ireland, Israel, Luxembourg, the Netherlands and Switzerland). Four countries reported high influenza activity: Denmark, Ireland, Norway and the United Kingdom (England).

Among 43 countries for which information on geographical spread was available, 14 were experiencing widespread activity, 5 regional activity, 9 local activity, and the remaining 15 no or sporadic activity.

Virological situation - week 01/2011

This week, pandemic influenza A(H1N1) 2009 and influenza B remain the predominant viruses circulating in the Region with relatively few influenza A(H3N2) viruses being detected.

Pandemic A(H1N1) 2009 dominated in 18 countries, influenza A and B co-dominated in 5 countries while influenza B was dominant in 4 countries.

Sentinel physicians collected 2005 respiratory specimens, of which 877 (44%) were positive for influenza virus: 648 (74%) were influenza A and 229 (26%) were influenza B.

Of the influenza A viruses, 592 were subtyped: 536 (91%) as pandemic A(H1) and 56 (9%) as A(H3).

In the 23 countries testing 20 or more sentinel specimens, influenza positivity ranged from 5% to 68%, with a median of 46% (mean: 43%). Influenza positivity was above 60% in 5 countries: Belgium, Ireland, Israel, Lithuania and the Netherlands.

Among specimens tested from non-sentinel sources, 5085 were positive for influenza: 3707 (73%) influenza A and 1378 (27%) influenza B.

Of the influenza A viruses, 2047 were subtyped: 1977 (97%) as pandemic A(H1) and 70 (3%) as A(H3).

Respiratory syncytial virus was also reported by some countries.

Since week 40/2010, 399 influenza viruses have been characterized antigenically: 179 were A(H1) pandemic A/California/7/2009 (H1N1)-like; 162 were B/Brisbane/60/2008-like (B/Victoria/2/87 lineage); 45 were A(H3) A/Perth/16/2009 (H3N2)-like; 12 were B/Florida/4/2006-like (B/Yamagata/16/88 lineage); and 1 was B/Bangladesh/3333/2007-like (B/Yamagata/16/88 lineage).

Based on the genetic characterization of 56 influenza viruses, 41 belonged to the pandemic A/California/7/2009 A(H1N1) clade; 5 belonged to the A(H3) clade represented by A/Perth/16/2009; 4 belonged to the subgroup represented by A/Hong Kong/2121/2010 in the A/Victoria/208/2009 A(H3) clade; 4 belonged to the B/Bangladesh/3333/2007 clade (Yamagata lineage); 1 to the B/Florida/4/2006 clade (Yamagata lineage); and 1 to the B/Brisbane/60/2008 clade (Victoria lineage).

Cumulative virological update - weeks 40/2010-01/2011

A total of 15 860 influenza virus detections were reported, of which 11 244 (71%) were influenza A and 4616 (29%) influenza B.

Of the influenza A viruses, 6539 were subtyped: 6104 (93%) as pandemic influenza A(H1), 433 (7%) as influenza A(H3) and 2 (less than 1%) as influenza A(H1).

Comment

ILI and ARI consultation rates have increased particularly in countries of the northern and western part of the European Region. Widespread activity has been reported by an increasing number of countries. Influenza activity is still low in other countries in the WHO European Region; but, current data may be incomplete following holidays in several countries.

In week 01/2011, across the Region as a whole, 44% of sentinel samples tested positive for influenza, corroborating the widespread influenza activity.

The co-circulation of influenza B with the pandemic A(H1N1) 2009 virus contrasts with the 2009/2010 season when little co-circulation of influenza B was seen.

Further information

The EuroFlu bulletin describes and comments on influenza activity in the 53 countries in the WHO European Region. For a current update on the influenza situation and WHO/Europe recommendations click here.

Further information can be obtained from the web sites of WHO/Europe, WHO headquarters and the European Centre for Disease Prevention and Control.

(...)

Network comments (where available)

England
- Due to bank holidays in weeks 52 and 1 GP surgeries were only open for three and four days respectively, which will have impacted GP consultation rates so data should be interpreted cautiously.
- A similar dip and subsequent increase in consultation rates is often seen at this time of year.
- Number of patients in England with confirmed or suspected influenza in critical care beds by age of patient:
  - week ending 15 Dec 2010
    - Under 5=10,
    - 5-15=9,
    - 16-64=141,
    - 65+=22,
    - Total=182;
  - week ending 23 Dec 2010
    - Under 5=26,
    - 5-15=17,
    - 16-64=366,
    - 65+=51,
    - Total=460;
  - week ending 30 Dec 2010
    - Under 5=42,
    - 5-15=24,
    - 16-64=586,
    - 65+=86,
    - Total=738;
  - week ending 6 Jan 2010
    - Under 5=30,
    - 5-15=17,
    - 16-64=640,
    - 65+=96,
    - Total=783.
- The overall number of severely ill patients with confirmed or suspected flu in critical care has continued rising.
- As at 06 January 2011 there were 783 patients with confirmed or suspected influenza in NHS critical care beds in England these patients occupied 22.5 % of available critical care beds nationally.
- For further information see (LINK)
Czech Republic
- During last week three new SARI cases with laboratory confirmed pandemic strain all at intensive and/or resuscitation care units were reported: 29-years-old male with no risk condition; 48 years-old female with diabetes and obesity; 54-years-old male with abdominal sepsis.
Malta
- situation stable
Scotland
- Continued increase in SARI cases.
- Small number of B cases and H3 cases also identified.
- Continued increase in SARI cases, majority of which are influenza A (H1N1) 2009.
Spain
- In Spain the information of severe illness due to influenza infection admitted to hospitals comes from a surveillance system developed during the 2009/2010 pandemic season for reporting severe hospitalised confirmed influenza cases.
- Since week 40/2010 and up to week 01/2011 245 severe hospitalised confirmed influenza cases have been reported.
- Severely affected are mostly young adults some without underlying conditions (16%).
- Most of the severe cases and deaths have been associated with A(H1N1)2009 and have not previously been vaccinated.

(...)
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**Giuseppe** · January 14, 2011, 11:45 AM

Main surveillance developments in week 1/2011 (03 ? 09 Jan 2011) (ECDC, Jan 14 2011, edited)

Main surveillance developments in week 1/2011 (03 ? 09 Jan 2011) (ECDC, Jan 14 2011, edited)

[Source: European Centre for Disease Prevention and Control (ECDC), full PDF document (LINK). Extract, edited.]

SURVEILLANCE REPORT

Weekly influenza surveillance overview

14 January 2011

Main surveillance developments in week 1/2011 (03 ? 09 Jan 2011)

This first page contains the main developments of this week and can be printed separately or together with the more detailed information following.

Most countries are now reporting regional or widespread influenza activity, with medium to high influenza-like illness/acute respiratory infection (ILI/ARI) consultation rates and increasing trends.
This is more prominent in Western European countries.
Forty-three per cent of sentinel swabs tested positive for influenza: 71% were type A, and of the type A viruses subtyped, 97% were A(H1N1) 2009.
Since week 40/2010, 1148 severe acute respiratory infection (SARI) cases, including 37 fatal cases, have been reported by seven countries.
In addition to the UK, other countries are now reporting cases requiring higher level care and deaths in young adults associated with influenza infection. Most are with A(H1N1) 2009 virus, but some are with B viruses as well.

Sentinel surveillance of ILI/ARI:

In addition to Denmark, Ireland and the UK (England) that had reported high ILI/ARI consultation levels the previous week, Norway has changed its indicator from medium to high.

Virological surveillance:

Sentinel physicians collected 1661 specimens, 715 (43%) of which tested positive for influenza.

Hospital surveillance of SARI:

During week 1/2011, 196 SARI cases were reported. The number of SARI cases by week of onset appears to be increasing (Figure 6). Males and females were equally affected.

Sentinel surveillance (ILI/ARI) - Weekly analysis ? epidemiology

In week 1/2011, 28 countries reported intensity of influenza activity (Table 1, Map 1).

In addition to Denmark, Ireland and the UK (England) that had reported high ILI/ARI consultation levels the previous week, Norway has changed its indicator from medium to high.

Medium intensity was again reported by Belgium, France, Italy, Luxembourg, Malta, Portugal, Spain and the UK (Scotland and Wales), with Bulgaria, Estonia, Germany, Greece, Iceland, the Netherlands and Slovenia this week raising their indicators to this level.

The remaining ten countries continued to report low intensity levels.

The four countries with high intensity differ from each other in their epidemiology. While Denmark reports the highest ILI consultation rates in children below 15 years of age, the age group predominantly affected in Ireland, Norway and the UK (England) appears to be that from 15 to 64 years, although the UK (England) also saw an early ILI peak in children during weeks 50 and 51/2010.

Further, while ILI consultation rates are still well below levels reported at the beginning of last year in Denmark and Norway, they have reached these levels in Ireland and exceeded them threefold in the UK (England).

All 29 countries reported on the geographic spread of influenza (Table 1, Map 2). Widespread activity continued to be seen in Belgium, Denmark, France, Ireland, the Netherlands, Norway, Portugal and the UK (England), and was newly reported by Estonia, Luxembourg, Spain and the UK (Scotland and Wales). Regional activity was still observed in Finland and Italy, and now in Lithuania. Fourteen countries reported sporadic or local activity. Austria was the only country still reporting no activity.

The trend indicator was reported by 28 countries: increasing trends by 22 countries and the UK (Scotland and Wales) and stable trends by the remaining countries (Table 1, Map 2).

(...)

Table 1: Epidemiological and virological overview by country, week 1/2011

[Country - Intensity - Geographic spread - Trend - No. of sentinel swabs - Dominant type - Percentage positive* - ILI per 100.000 - ARI per 100.000]

Austria - Low - No activity - Unknown (no information available) - 11 - None - 45.5 - ... - 15.5
Belgium - Medium - Widespread - Increasing - 53 - A - 67.9 - 487.8 - 1908.8
Bulgaria - Medium - Local - Increasing - 1 - None - 0.0 - ... - 1227.4
Cyprus - Low - Sporadic - Stable - ... - ... - 0.0 - ...* - ...*
Czech Republic - Low - Sporadic - Increasing - 16 - A - 37.5 - 30.4 -932.5
Denmark - High - Widespread - Decreasing - 32 - None - 37.5 - ... - ...
Estonia - Medium - Widespread - Increasing - 41 - None - 22.0 - 10.0 - 317.6
Finland - Unknown (no information available) - Regional - Stable - 25 - B, A(H1)2009 - 48.0 - ... - ...
France - Medium - Widespread - Increasing - 219 - A(H1N1)2009 - 42.0 - ... - 2493.1
Germany - Medium - Local - Increasing - 112 - A(H1N1)2009 - 45.5 - ... - 1217.4
Greece - Medium - Sporadic - Increasing - 7 - A(H1N1)2009 - 42.9 - 106.0 - ...
Hungary - Low - Sporadic - Increasing - 90 - A(H1)2009 - 15.6 - 125.8 - ...
Iceland - Medium - Local - Increasing - ... - ... - 0.0 - 14.8 - ...
Ireland - High - Widespread - Increasing - 116 - A(H1)2009 - 62.9 - 204.2 - ...
Italy - Medium - Regional - Increasing - 52 - A(H1N1)2009 - 32.7 - 451.3 - ...
Latvia - Low - Local - Increasing - 1 - A(H1)2009 - 0.0 - 15.7 - 1014.4
Lithuania - Low - Regional - Increasing - ... - ... - 0.0 - 41.1 - 646.9
Luxembourg - Medium - Widespread - Stable - 34 - B, A(H1)2009 - 58.8 - ...* - ...*
Malta - Medium - Local - Increasing - ... - ... - 0.0 - ...* - ...*
Netherlands - Medium - Widespread - Increasing - 36 - None - 63.9 - 87.3 - ...
Norway - High - Widespread - Increasing - 43 - B - 53.5 - 165.1 - ...
Poland - Low - Sporadic - Increasing - 22 - A(H1)2009 - 18.2 - 90.8 - ...
Portugal - Medium - Widespread - Increasing - 16 - A, B - 62.5 - 95.1 - ...
Romania - Low - Sporadic - Increasing - 48 - None - 8.3 - 20.7 - 722.8
Slovakia - Low - Sporadic - Stable - 1 - None - 0.0 - 120.8 - 1249.4
Slovenia - Medium - Local - Increasing - 48 - A(H1)2009 - 50.0 - 30.0 - 1677.4
Spain - Medium - Widespread - Increasing - 244 - A(H1N1)2009 - 46.3 - 208.5 - ...
Sweden - Low - Sporadic - Increasing - 17 - A(H1)2009 - 47.1 - 16.9 - ...
UK - England - High - Widespread - Stable - 328 - A, B - 39.3 - 108.4 - 667.4
UK - Northern Ireland - ... - ... - ... - ... - ... - ... 0.0 - ... - ...
UK - Scotland - Medium - Widespread - Increasing - 48 - A(H1N1)2009 - 56.3 - 18.2 - 227.0
UK - Wales - Medium - Widespread - Increasing - ... - ... - 0.0 - 92.8 - ...
Europe - ... - ... - ... - 1661 - ... - 43.0 - ... - ...

*Incidence per 100 000 is not calculated for these countries as no population denominator is provided.

Note: Liechtenstein is not reporting to the European Influenza Surveillance Network

Description of the system

This surveillance is based on nationally organized sentinel networks of physicians, mostly general practitioners (GPs), covering at least 1?5% of the population in their countries. All EU/EEA Member States (except Liechtenstein) are participating. Depending on their country?s choice, each sentinel physician reports the weekly number of patients seen with influenza-like illness (ILI), acute respiratory infection (ARI) or both to a national focal point. From the national level, both numerator and denominator data are then reported to the European Surveillance System (TESSy) database. Additional semi-quantitative indicators of intensity, geographic spread and trend of influenza activity at the national level are also reported.

Weekly analysis ? virology

In week 1/2011, 25 countries reported virological data.

Sentinel physicians collected 1661 specimens, 715 (43%) of which tested positive for influenza (Tables 1 and 2). This represents the first decrease compared to the previous week (45.8%) since week 46/2010 (Figure 3). However, proportions of influenza- positive sentinel samples of more than 60% were reported by Belgium, Ireland, the Netherlands and Portugal, followed by proportions ≥ 50% in Luxembourg, Norway, Slovenia and the UK (Scotland) (Table 1). In addition, 3740 non-sentinel source specimens (i.e. specimens collected for diagnostic purpose in hospitals) were reported positive for influenza virus.

Of the 4455 influenza viruses detected during week 1/2011, 3180 (71.4%) were type A and 1275 (28.6%) were type B.

Of the 484 sentinel influenza A viruses that were subtyped, 470 (97.1%) were A(H1N1) 2009 and 14 (2.9%) were A(H3) viruses (Table 2).

Since week 40/2010, 9866 (72.7%) of the 13 579 influenza virus detections in sentinel and non-sentinel specimens, were type A and 3711 (27.3%) were type B. Of the 2163 sentinel influenza A viruses subtyped, 2063 (95.4%) were A(H1N1) 2009, 99 (4.6%) were A(H3) and one, detected in Poland in week 50/2010, was A(H1) (Table 2). Trends of virological detections since week 40/2010 are shown in Figures 1?3.

Since week 40/2010, 373 influenza viruses from sentinel and non-sentinel specimens have been characterised antigenically (Figure 4): 161 (43.2%) as A/California/7/2009 (H1N1)-like; 47 (12.6%) as A/Perth/16/2009 (H3N2)-like; 155 (41.5%) as B/Brisbane /60/2008-like (Victoria lineage); and 10 (2.7%) as B/Florida/4/2006-like (Yamagata lineage).

In terms of antiviral resistance, since week 40/2010, a total of 185 influenza A(H1N1) 2009 viruses and six influenza B viruses have been tested for susceptibility to neuraminidase inhibitors. Data were provided for either single location substitution (e.g. H275Y by pyrosequencing or targeted gene fragment sequencing) or multiple location substitution analysis (full gene sequencing) and/or phenotyping (IC50 determination) and should be interpreted in this context (Table 2). All but two viruses were sensitive to both oseltamivir and zanamivir. Two A(H1N1) 2009 viruses from the UK had the H275Y substitution known to confer resistance to oseltamivir while retaining susceptibility to zanamivir. Both viruses were from patients who had not been treated with oseltamivir.

More details on circulating viruses can be found in this report prepared by the Community Network of Reference Laboratories (CNRL) coordination team. Also, a detailed analysis of the viruses isolated in the UK was published last week in Eurosurveillance indicating no evidence of any antigenic changes in the A(H1N1) 2009 and type B viruses in that country and a good match with the seasonal vaccine viruses.

In week 1/2011, 16 countries reported 1426 respiratory syncytial virus (RSV) detections, a number that has decreased for the second consecutive week (Figure 5).

Table 2: Weekly and cumulative influenza virus detections by type, subtype and surveillance system, weeks, 40/2010?1/2011

[Virus type/subtype - Current Period: Sentinel - Non-Sentinel / Season: Sentinel - Non-Sentinel]

Influenza A - 539 - 2641 / 2361 - 7507
- A (H1) 2009 - 470 - 1123 / 2063 - 3135
- A (subtyping not performed) - 55 - 1505 / 198 - 4280
- A (not subtypable) - 0 - 0 / 0 - 0
- A (H3) - 14 - 13 / 99 - 92
- A (H1) - 0 - 0 / 1 - 0
Influenza B - 176 - 1099 / 889 - 2822
Total Influenza - 715 - 3740 / 3250 - 10329

Note: A(H1)2009, A(H3) and A(H1) includes both N-subtyped and non-N-subtyped viruses

(...)

Table 3: Antiviral resistance by influenza virus type and subtype, weeks 40/2010?51/2010

[Virus type and subtype - Resistance to neuraminidase inhibitors: Oseltamivir (Isolated Tested, Resistant n (%) - Zanamivir (Isolated Tested, Resistant n (%) / Resistance to M2 inhibitors: Isolates tested, Resistant n (%)]

A(H3) - 0 - 0 - 0 - 0 / 0 - 0
A(H1) - 0 - 0 - 0 - 0 / 0 - 0
A(H1)2009 - 185 - 2 (1.1) - 185 - 0 / 0 - 0
B - 6 - 0 - 6 - 0 / NA* - NA*

* NA - not applicable, as M2 inhibitors do not act against influenza B viruses

(...)

Country comments

UK (Scotland):
- A small number of type B virus cases and H3 cases were identified. Continued increase in SARI cases, the majority of which are influenza A(H1N1) 2009.

Description of the system

According to the nationally defined sampling strategy, sentinel physicians take nasal or pharyngeal swabs from patients with influenza-like illness (ILI), acute respiratory infection (ARI) or both and send the specimens to influenza-specific reference laboratories for virus detection, (sub-)typing, antigenic or genetic characterisation and antiviral susceptibility testing.

For details on the current virus strains recommended by WHO for vaccine preparation, click here.

Hospital surveillance ? severe acute - respiratory infection (SARI) - Weekly analysis ? SARI

Since week 40/2010, 1148 SARI cases, including 37 fatal cases, have been reported by seven countries (Table 4). Only three countries?Belgium, Romania and Slovakia?are collecting syndromic SARI cases. The remaining countries are reporting laboratory- confirmed hospitalised influenza cases or severe influenza cases admitted to intensive care, as in France.

During week 1/2011, 196 SARI cases were reported. Males and females were equally affected (Table 5). The number of SARI cases by week of onset appears to be increasing still (Figure 6). However, these increases may simply reflect a new system and new countries, few of which have a baseline for these data.

Of the 317 cases that tested positive for influenza in week 1/2011, 311 (98.1%) were infected by type A and 6 (1.9%) by type B viruses (Table 6). Of the 284 type A viruses subtyped, 283 (99.6%) were A(H1) 2009 and one was A(H3). Since week 40/2010, 495 (97.8%) of 506 influenza viruses detected were type A, and 454 (99.1%) of 458 type A viruses subtyped were A(H1) 2009.

Of the 1148 reported cases since week 40/2010, 402 (35.0%) were admitted to intensive care with 187 (16.3%) requiring ventilatory support (Table 8).

Table 4: Cumulative number of SARI cases, weeks 40/2010?1/2011

[Country - No. of SARI cases - Incidence of SARI cases per 100,000 population - Number of fatal cases reported - Incidence of fatal cases per 100,000 population - Estimated population covered]

Austria - 9 - ... - 1 - ... - ...
Belgium - 496 - ... - ... - ... - ...
Spain - 345 - ... - 16 - ... - ...
France - 171 - ... - 11 - ... - ...
Portugal - 39 - ... - 4 - ... - ...
Romania - 84 - 1.31 - 5 - 0.08 - 6.413.821
Slovakia - 4 - ... - ... - ... - ...
Total - 1148 - ... - 37 - ... - ...

(...)

Table 5: Number of SARI cases by age and gender, week 1/2011

[Age groups - Male - Female - Unknown]

Under 2 - 18 - 14 - ...
2-17 - 9 - 3 - ...
18-44 - 27 - 28 - ...
45-59 - 27 - 19 - 2
>=60 - 19 - 27 - 1
Unknown - ... - 1 - 1
Total - 100 - 92 - 4

Table 6: Number of SARI cases by influenza type and subtype, week 1/2011

[Virus type/subtype - Number of cases during current week - Cumulative number of cases since the start of the season]

Influenza A - 311 - 495
- A(H1) 2009 - 283 - 454
- A(H1) - ... - ...
- A(H3) - 1 - 4
- A(subtyping not performed) - 27 - 37
Influenza B - 6 - 11
Unknown - 150 - 613
Total - 467 - 1119

Table 7: Number of SARI cases by antiviral treatment, weeks 40/2010?1/2011

[Antiviral treatment - Number of patients who received prophylaxis - Number of patients who received anti-viral treatment]

Oseltamivir - 1 - 328
Zanamivir - ... - 7
Other (or combinations with other) - 2 - 3
Unknown - 1013 - 739
None - 132 - 71
Total - 1148 - 1148

Table 8: Number of SARI cases by level of care and respiratory support, weeks 40/2010?1/2011

[Respiratory support - ICU - Inpatient ward - Other - Unknown]

No respiratory support available - ... - 1 - ... - ...
No respiratory support necessary - 44 - 35 - 245 - ...
Oxygen therapy - 40 - 40 - 195 - ...
Respiratory support given unknown - 131 - 4 - 135 - 83
Ventilator - 187 - 2 - 5 - 1
Total - 402 - 82 - 580 - 84

Table 9: Number of SARI cases by vaccination status, week 1/2011

[Vaccination Status - Number Of Cases - Percentage of cases]

Both, monovalent 2009 pandemic H1N1 and seasonal 2010 vaccination - 6 - 3.1
Monovalent 2009 pandemic H1N1 vaccination - 3 - 2
Not vaccinated - 79 - 40.3
Seasonal 2010 vaccination - 11 - 6
Unknown - 97 - 49.5
TOTAL - 196 - ...

(...)

Table 10: Number of underlying conditions in SARI cases by age group, weeks 40/2010?1/2011

[Underlying condition/risk factor - 0-11 months - 1-4 y - 5-14 y - 15-24 y - 25-64 y - >=65 y]

Asthma - ... - 1 - 1 - 1 - 1 - ...
Cancer - ... - 1 - ... - ... - 2 - 2
Diabetes - ... - ... - ... - ... - 36 - 15
Chronic heart disease - 4 - ... - ... - ... - 25 - 15
Chronic lung disease - 2 - 1 - ... - 1 - 14 - 6
Pregnancy - ... - ... - ... - 6 - 22 - ...
Underlying condition unknown - 15 - 23 - 8 - 14 - 157 - 26
Other (including all other conditions) - 201 - 144 - 50 - 11 - 243 - 96

Note: The data is collected for asthma, cancer, diabetes, chronic heart disease, HIV/other immune deficiency, kidney-related conditions, liver-related conditions, chronic lung disease, neurocognitive disorder (including seizure), neuromuscular disorder, obesity (BMI between 30 and 40), morbid obesity (BMI above 40), pregnancy, other, underlying condition unknown and for no underlying condition.

Table 11: Additional clinical complications in SARI cases by age group, weeks 40/2010?1/2011

[Additional clinical complications - 0-11 months - 1-4 y - 5-14 y - 15-24 y - 25-64 y - >=65 y]

Acute respiratory distress syndrome - 24 - 23 - 7 - 13 - 129 - 23
Bronchiolitis - 1 - ... - ... - ... - 1 - ...
Pneumonia (secondary bacterial infection) - 11 - 15 - 5 - 11 - 190 - 35
Sepsis/Multi-organ failure - ... - ... - ... - ... - ... - 1
None - 3 - 4 - ... - 3 - 16 - 9
Other - ... - ... - ... - ... - 3 - ...
Unknown - 183 - 128 - 47 - 6 - 161 - 92

Country comments

Czech Republic:
- During the last week, three new SARI cases with laboratory-confirmed pandemic strain were reported, all at intensive and/or resuscitation care units: 29-year-old male with no risk condition; 48-year-old female with diabetes and obesity; 4-year-old male with abdominal sepsis.
Spain:
- In Spain the information of severe illness due to influenza infection admitted to hospitals comes from a surveillance system developed during the 2009/2010 pandemic season for reporting severe hospitalised confirmed influenza cases. From week 40/2010 to week 01/2011, 245 severe hospitalised confirmed influenza cases have been reported. Those severely affected are mostly young adults, some without underlying conditions (16%). Most of the severe cases and deaths have been associated with A(H1N1)2009 and have not previously been vaccinated.
Ireland:
- As of week 48/2010, 71 confirmed cases of influenza A(H1N1) 2009 have been admitted to intensive care in Ireland.
Malta:
- Situation unchanging.
United Kingdom (England):
- Due to bank holidays in weeks 52/2010 and 1/2011, general practitioner (GP) surgeries were only open for three and four days respectively, impacting GP consultation rates; as such data should be interpreted cautiously. A similar dip and subsequent increase in consultation rates is often seen at this time of year. The following is a list of the number of patients in England with confirmed or suspected influenza in critical care beds by age of patient: for the week ending 15 Dec 2010, <5=10, 5?15=9, 16?64=141, >65=22, total=182; week ending 23 Dec 2010, <5=26, 5-15=17, 16-64=366, >65=51, total=460; week ending 30 Dec 2010, <5=42, 5?15=24, 16?64=586, >65=86, total=738; week ending 6 Jan 2010, <5=30, 5?15=17, 16?64=640, >65=96, total=783. The overall number of severely ill patients with confirmed or suspected flu in critical care has continued to rise. As of 06 January 2011, there were 783 patients with confirmed or suspected influenza in NHS critical care beds in England. These patients occupied 22.5 % of available critical care beds nationally.
- These levels are higher than any seen in the 2009 pandemic. As of 5 January 2011, 50 fatal cases have been verified by the Health Protection Agency (HPA) as related to influenza infection. Of these cases, 45 have been associated with H1N1 (2009) infection and five with influenza B infection. The deaths have been mainly in younger adults and children, with five cases younger than 5 years of age, eight cases from 5 to 14 years, 33 cases from 15 to 64 years and four cases older than 64 years. Thirty-three of 48 (69%) fatal cases with available information were in one of the CMO-defined clinical risk groups for vaccination. The leading reported clinical risk factors were underlying neurological disease (n=11) and respiratory disease including asthma (n=13). Of cases with available information on immunisation history, 36 of 39 cases had not received 2010/11 trivalent influenza vaccine more than two weeks before illness onset. Thirty-three of 34 cases had not received monovalent pandemic influenza vaccination last season. For further information see (LINK) and the HPA output at (LINK).
- In addition, communications were received from Belgium, Denmark and Norway for week 2 and will be added next week.

The report text was written by an editorial team at the European Centre for Disease Prevention and Control (ECDC): Eeva Broberg, Flaviu Plata, Phillip Zucs and Ren? Snacken. The bulletin text was reviewed by the Community Network of Reference Laboratories for Human Influenza in Europe (CNRL) coordination team: Adam Meijer, Rod Daniels, John McCauley and Maria Zambon. On behalf of the EISN members the bulletin text was reviewed by Bianca Snijders (RIVM Bilthoven, The Netherlands) and Thedi Ziegler (National Institute for Health and Welfare, Finland). Finally, it was reviewed by WHO/Europe.

Maps and commentary used in this Weekly Influenza Surveillance Overview (WISO) do not imply any opinions whatsoever of ECDC or its partners on the legal status of the countries and territories shown or concerning their borders.

All data published in the WISO are up-to-date on the day of publication. Past this date, however, published data should not be used for longitudinal comparisons as countries tend to retrospectively update their numbers in the database.

? European Centre for Disease Prevention and Control, Stockholm, 2010

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**Giuseppe** · January 14, 2011, 12:08 PM

EpiSouth Weekly Epi Bulletin ? N?147 - 05 January 2010 ? 11 January 2011 (Extract, edited)

EpiSouth Weekly Epi Bulletin ? N?147 - 05 January 2010 ? 11 January 2011 (Extract, edited)

[Source: EpiSouth, full PDF document (LINK). Extract, edited.]

EpiSouth Weekly Epi Bulletin ? N?147 - 05 January 2010 ? 11 January 2011

The objective of the bulletin is to report new heath events occurring outside and inside EpiSouth area that have potential implications on EpiSouth population. It does not aim to provide an exhaustive review of international alerts. Since 2006, The French public health Institute (InVS) is issuing an online epidemic intelligence bulletin (Bulletin hebdomadaire International - BHI). In order to limit duplication and to make this already verified information available to a larger audience, information relating to health events of interest for EpiSouth population are translated and integrated in the relevant e-web sections. Despite all verifications, WP6 team would not be responsible for potential errors. The recipient is responsible for the cautious use of this information. Neither the European Commission nor any person acting on behalf of the Commission is liable for the use that may be made of the information contained in this report. Data maps and commentary used in this document do not imply any opinion of EpiSouth countries or its partners on the legal status of the countries and territories shown or concerning their borders.

INDEX e-WEB n?147

A(H5N1) Human influenza ? Egypt
A(H5N1) Avian influenza ? Bangladesh
?INSIDE? Events: none
?OUTSIDE? events:
- Dioxin contaminated product ? Germany

Location: Egypt - Event: A(H5N1) ? Human

On 10th January 2011, the Egyptian Ministry of Health reported a new A(H5N1) human infection.
The 120th case is:
- A 10 year-old boy from Giza governorate (cf. map1).
- He developed symptoms on 5th January 2011
- He was hospitalised on 8th January 2011 and is in stable condition.
- Exposure to poultry was documented.
- In this governorate, this is the 1st A(H5N1) human case reported.
In Egypt, the last human case was reported on 05th January 2011 in Sharkia, Qena, Ismailia and Daqahliya Governorates (cf. eWEB n?146).
Since the 1st case of bird flu in Egypt, the case count is 120 cases including 40 deaths.

Comments

The available information does not indicate a change in the epidemiology of the virus in Egypt.

Location: Bangladesh - Event: A(H5N1) ? Epizootic

On 10th January 2011, the health authorities of Bangladesh reported to OIE an outbreak of an A(H5N1) avian influenza virus in a commercial poultry farm located in the district of Dhaka (cf. map 2).
In Bangladesh, the last A(H5N1) epizootic was reported on 20th May 2010 in poultry in the division of Rajshahi in the Midwestern corner of the country (cf. eWEB n?115).

Comments

A(H5N1) epizootics were regularly recorded in Bangladesh in 2010, especially during the 1st quarter of 2010 (cf. e-WEB n?97, 101 and 115).

REPORT OF NEW HEALTH EVENTS OCCURRING OUTSIDE THE EPISOUTH AREA (Not occurring in one or several EpiSouth countries)

Area: Germany - Event: Dioxin contaminated feed food

On 27th December 2010, the German authorities informed the European Commission?s Rapid Alert System for Food and Feed (RASFF) of the contamination by dioxin of fatty acids used for the production of animal feed.
German officials halted sales from more than 4700 small farms after dioxin was found in some feed for chicken and pigs.
South Korea and Slovakia banned sales of some animals imported from Germany, while Britain and the Netherlands were investigating foods like mayonnaise. Few batches of feed for breeding poultry were delivered to Denmark and France
As precautionary measures and pending laboratory tests for the presence of dioxin, all fat feed produced by the company from 12 November 2010 is considered as being potentially contaminated.

Comments

The dioxin can cause severe health problems in humans, including miscarriages and is known to be a cancer-causing agent.
The risk of further dissemination in the EpiSouth countries appears to be low.

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**Giuseppe** · January 18, 2011, 01:51 PM

ECDC: Influenza Season 2010-2011: Antigenic Characteristics of Recent Influenza virus isolates (only figures)

Full PDF document: http://www.ecdc.europa.eu/en/publica...0_December.pdf

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Attached Files

**Giuseppe** · January 18, 2011, 01:53 PM

Re: ECDC: Influenza Season 2010-2011: Antigenic Characteristics of Recent Influenza virus isolates (only figures)

Source: ECDC, http://www.ecdc.europa.eu/en/publica...0_December.pdf

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Attached Files

**Giuseppe** · January 18, 2011, 02:01 PM

Influenza virus characterisation - Summary for Europe, December 2010 (ECDC, Jan 18 2011, extract, edited): A/Northern Ireland/1/2010?showed a reduced level of reactivity with the majority of sera

Influenza virus characterisation - Summary for Europe, December 2010 (ECDC, Jan 18 2011, extract, edited)

[Source: European Centre for Disease Prevention and Control, full PDF Document, (LINK). Extract, edited. Images are available also here: (LINK).]

SURVEILLANCE REPORT

Community Network of Reference Laboratories (CNRL) for Human Influenza in Europe

Influenza virus characterisation - Summary for Europe, December 2010

Influenza virus characterisation, December 2010

Since the September 2010 report, very few samples were received from ECDC-affiliated countries until December 2010.

Table 1 shows a list of the ECDC-affiliated countries that have sent viruses or clinical samples collected since 1 September 2010.

Pandemic A(H1N1) 2009 viruses were received from the UK, Italy, Spain, Portugal and Luxembourg; H3N2 viruses from the UK, Germany, Greece, Spain and Portugal. Influenza B viruses were received from the same countries with B-Victoria-lineage viruses predominating over B/Yamagata-lineage viruses.

Table 2 shows the results of haemagglutination inhibition tests carried out on A(H1N1) 2009 viruses from Europe using a panel of post-infection ferret antisera.

The results show that the vast majority of viruses had similar levels and patterns of reactivity to the antisera and remained antigenically similar to the vaccine virus A/California/7/2009.

One virus?A/Northern Ireland/1/2010?showed a reduced level of reactivity with the majority of sera; sequencing of this virus is ongoing.

Figure 1 shows a phylogenetic analysis of the HA1 coding region of the HA gene of H1N1 viruses.

In the figure, viruses collected in ECDC-affiliated countries are highlighted in yellow and additionally colour coded by the date of collection.

From the figure it can be seen that recent isolates from Europe do not cluster in the tree.

A recently collected virus from Italy (A/Milano/3/2010) clustered with a genetic group that had been observed in the Southern Hemisphere in 2010*.

Two viruses from England collected in November are shown in the phylogenetic tree; these viruses do not cluster together.

The genetic characteristics of viruses isolated more recently in the UK have been described elsewhere?.

The analysis of all A(H1N1) viruses collected in December, now received at the WHO CC from ECDC-affiliated countries, is in progress.

Fifteen H3N2 viruses have been received from ECDC-affiliated countries.

These viruses have shown highly variable agglutination of red blood cells and this variable agglutination has made HI assays difficult to assess.

Phylogenetic analysis of the HA1-coding region of the HA gene has been undertaken and results of representative strains are shown in Figure 2. All but one of the viruses collected recently from ECDC-affiliated countries cluster with an emerging phylogenetic group that has been recognised around the world in 2010.

This phylogenetic group clusters within the A/Victoria/208/2009 genetic clade. The other virus sequence (A/England/4820166/2010) falls into the A/Perth/16/2009 phylogenetic clade and shares two additional amino acid substitutions with viruses collected previously in Greece, Argentina and the West Indies compared with the reference strains in the clade.

Table 3 shows the results of haemagglutination inhibition tests carried out on influenza B Victoria-lineage viruses from Europe using a panel of post-infection ferret antisera. As expected, the antiserum raised against the egg-propagated vaccine virus B/Brisbane/60/2008 shows low cross-reactivity with all viruses propagated exclusively in tissue culture.

Antisera raised against viruses that are phylogenetically closely related to the vaccine virus, but propagated in mammalian cells, can be used to assess the antigenic similarity of viruses within the B/Brisbane/60/2008 genetic clade.

Antisera raised against B/Paris/1762/2009, B/Hong Kong/514/2009 and B/Odessa/3886/2010 show good reactivity against the majority of the viruses tested with these antisera. Two viruses showed a different pattern of reactivity; these viruses (B/England /81/2010 and B/England/121/2010) reacted well only with a sheep hyper-immune serum raised against B/Malaysia/2506/04.

Figure 3 shows the phylogenetic analysis of the HA1 coding region of the HA gene of influenza B Victoria-lineage viruses.

The vast majority of the recently collected viruses from ECDC-affiliated countries fall into the Brisbane/60/2008 phylogenetic clade. However, B/England/81/2010 clustered differently with an influenza B virus collected in England earlier in the year; the altered antigenic profile of this virus is consistent with the altered phylogenetic clustering.

A haemagglutination inhibition test using a panel of post-infection ferret antisera was carried out on the two influenza B Yamagata-lineage viruses, collected from Europe, that were propagated (Table 3). Both viruses reacted well with antisera raised against B/Bangladesh/3333/2008 and against recent viruses from the B/Bangladesh/3333/2008 clade (B/Algeria/G-846/2008 and B/Wisconsin/1/2010). However, it was striking that B/Niedersachen/1/2010 showed a good reactivity with antiserum raised against the vaccine virus (B/Florida/4/2006) recommended for use in vaccines for the 2008/2009 Northern Hemisphere influenza season. Phylogenetic analysis of viruses of the influenza B Yamagata-lineage is ongoing.

* Barr IG, Cui L, Komadina N, et al. A new pandemic influenza A(H1N1) genetic variant predominated in the winter 2010 influenza season in Australia, New Zealand and Singapore. Euro Surveill. 2010;15(42):pii=19692.
? Ellis J, Galiano M, Pebody R, et al; Virological analysis of fatal influenza cases in the United Kingdom during the early wave of influenza in winter 2010/11. EuroSurveill. 2011;16(1): pii=19760.

Table 1: Summary of received specimens collected since 1 September 2010

[Collection Month - Country, Virus received: Pandemic A(H1N1), No. / Grown - H3, No. / Grown - B-Victoria, No. / Grown - B-Yamagata, No. / Grown]

SEPTEMBER
- United Kingdom - ... / ... - 2 / 0 - ... / ... - ... / ...
OCTOBER
- France - ... / ... - ... / ... - 4 / 4 - ... / ...
- Germany - ... / ... - 2 / 2* - ... / ... - 1 / 1
- Greece - ... / ... - 1 / 1* - ... / ... - ... / ...
- Portugal - ... / ... - ... / ... - 3 / in progress - ... / ...
- Spain - ... / ... - 1 / 1* - ... / ... - ... / ...
- United Kingdom - 1 / 1 - 1 / 1* - 2 / 2 - ... / ...
NOVEMBER
- Italy - 3 / 3 - ... / ... - 3 - in progress - ... / ...
- Portugal - ... / ... - 1 / 1* - 15 / in progress - ... / ...
- Spain - 5 / 3 - ... / ... - 1 / in progress - ... / ...
- United Kingdom - 6 / 6 - 2 / 2* - 8 / 8 - 1 / 1
DECEMBER
- Italy - 1 / in progress - ... / ... - 1 / 1 - ... / ...
- Luxembourg - 5 / in progress - ... / ... - 1 / in progress - ... / ...
- Portugal - 1 / in progress - ... / ... - 14 / in progress - ... / ...
- Spain - 4 / in progress - ... / ... - 1 / in progress - ... / ...
JANUARY
- Portugal - ... / ... - ... / ... - 1 / in progress - ... / ...
Total = 92 - 26 / 13 - 10 / 8 - 54 / 15 - 2 / 2

* Awaiting antigenic characterisation

Table 2: Antigenic analysis of A(H1N1) viruses

(...)

Note to the figures:

The phylogenetic trees were constructed using maximum parsimony in PAUP (Sinauer Associates). The bars indicate the proportion of nucleotide changes in the sequence. Reference strains are viruses to which post-infection ferret antisera have been developed. The colours indicate the date of sample collection. Isolates from ECDC countries are in italics and highlighted in yellow. Sequences for some of the viruses from non-European countries were recovered from GISAID and we acknowledge all laboratories submitting sequences.

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**Giuseppe** · January 21, 2011, 11:04 AM

EuroFlu - Weekly Electronic Bulletin - Week 2 : 10/01/2011-16/01/2011 - 21 January 2011, Issue N? 385 (Extract, edited): Ireland reported severe impact on its health care capacity

EuroFlu - Weekly Electronic Bulletin - Week 2 : 10/01/2011-16/01/2011 - 21 January 2011, Issue N? 385 (Extract, edited)

[Source: EuroFlu, full page: <cite cite="http://www.euroflu.org/cgi-files/bulletin_v2.cgi">EuroFlu - Bulletin Review</cite>. Extract, edited.]

EuroFlu - Weekly Electronic Bulletin - Week 2 : 10/01/2011-16/01/2011 - 21 January 2011, Issue N? 385

Continued slow increase in influenza activity across Europe

This issue is based on data reported in week 2/2011 by 46 Member States in the WHO European Region.
Influenza activity has progressed across the Region following a west-to-east trend.
44% of sentinel specimens were positive for influenza.
Pandemic influenza A(H1N1) 2009 remains the dominant virus, particularly in the western part of the Region.
Countries continue to report cases of severe disease caused mainly by pandemic influenza A(H1N1) 2009 virus infections (see network comments).

Current situation - week 02/2011

Of the 38 countries reporting on consultation rates for influenza-like illness (ILI) and acute respiratory infection (ARI), 20 reported increases while 2 reported decreases.

In the remaining 16 countries, consultation rates were largely unchanged.

In general, the highest consultation rates were reported for children aged 0-14 years. Information on the intensity of influenza activity was available for 40 countries.

Most countries reported medium (24) or low (13) activity, while 1 (Luxembourg) reported very high influenza activity and 2 others (Ireland and Norway) reported high activity.

Influenza was reported to be widespread in 15 countries, regional in 7 countries and local in 7 countries; 11 countries reported no or sporadic activity.

Influenza levels were highest in the western part of the Region.

Of the 23 countries reporting on the impact of influenza on health care systems, 19 described it as low overall. Ireland reported severe impact on its health care capacity, while 3 other countries (Estonia, Georgia and Israel) reported moderate impact.

Virological situation - week 2/2011

Pandemic influenza A(H1N1) 2009 continued to predominate in western and northern Europe, while influenza A and B mainly co-dominated in the eastern part of the Region.

Influenza B was reported to be dominant in a few countries.

Sentinel physicians collected 2886 respiratory specimens, of which 1263 (44%) were positive for influenza virus: 912 (72%) were influenza A and 351 (28%) were influenza B.

Of the influenza A viruses, 813 were subtyped: 769 (95%) as pandemic A(H1) and 44 (5%) as A(H3).

In the 24 countries testing 20 or more sentinel specimens, influenza positivity ranged from 12% to 76%, with a median of 44% (mean: 43%).

In addition, 4515 non-sentinel specimens were reported positive for influenza: 3183 (70%) influenza A and 1332 (30%) influenza B.

Of the influenza A viruses, 1875 were subtyped: 1842 (98%) as pandemic A(H1) and 33 (2%) as A(H3).

In addition, 20 countries reported circulation of respiratory syncytial virus.

Since week 40/2010, 620 influenza viruses have been characterized antigenically: 361 were A(H1) pandemic A/California/7/2009 (H1N1)-like; 184 were B/Brisbane/60/2008-like (B/Victoria/2/87 lineage); 62 were A(H3) A/Perth/16/2009 (H3N2)-like; and 13 were B/Florida/4/2006-like (B/Yamagata/16/88 lineage).

Based on the genetic characterization of 62 influenza viruses, 41 belonged to the pandemic A/California/7/2009 A(H1N1) clade; 9 belonged to the A(H3) clade represented by A/Perth/16/2009; 5 belonged to the subgroup represented by A/Hong Kong/2121/2010 in the A/Victoria/208/2009 A(H3) clade; 1 belonged to the A(H3) clade represented by A/Victoria/208/2009; 4 belonged to the B/Bangladesh/3333/2007 clade (Yamagata lineage); 1 belonged to the B/Florida/4/2006 clade (Yamagata lineage), and 1 to the B/Brisbane/60/2008 clade (Victoria lineage).

Cumulative virological update - weeks 40/2010-2/2011

A total of 22 579 influenza virus detections were reported, of which 16 055 (71%) were influenza A and 6524 (29%) influenza B.

Of the influenza A viruses, 9866 were subtyped: 9327 (95%) as pandemic influenza A(H1), 537 (5%) as influenza A(H3) and 2 (less than 1%) as influenza A(H1).

Comment

ILI and ARI consultation rates continue to rise, following a west-to-east progression across the Region. However, several countries are reporting low influenza activity, mainly in the central part of the Region. In week 2/2011, 44% of sentinel samples tested positive for influenza, similarly to previous weeks. Pandemic influenza A(H1N1) 2009 remains the dominant virus in circulation in most countries.

Further information

The EuroFlu bulletin describes and comments on influenza activity in the 53 countries in the WHO European Region. For an update on the influenza situation and WHO/Europe recommendations, see the WHO/Europe web site.

Further information can be obtained from the web sites of WHO/Europe, WHO headquarters and the European Centre for Disease Prevention and Control.

(...)

Network comments (where available)

England
- Number of patients in England with confirmed or suspected influenza in critical care beds by age of patient:
  - week ending 6 Jan 2010
    - Under 5=30,
    - 5-15=17,
    - 16-64=640,
    - 65+=96,
    - Total=783.
  - week ending 13 Jan 2010
    - Under 5=18,
    - 5-15=8,
    - 16-64=534,
    - 65+=101,
    - Total=661.
  - The overall number of severely ill patients with confirmed or suspected flu in critical care has reduced.
  - As at 13 January 2011, there were 661 patients with confirmed or suspected influenza in NHS critical care beds in England - these patients occupied 19 % of available critical care beds nationally.
  - For further information see (LINK)
Czech Republic
- During last week three additional SARI cases with laboratory-confirmed pandemic strain were reported - all males (56; 57 and 60 years old) with underlying conditions.
Latvia
- Two firsts death cases have been confirmed. Both were associated with A(H1N1)2009.
Luxembourg
- In wk2/2011 Luxembourg detected some double infections with influenza A (H1N1) 2009 and B.
Malta
- situation stable
Russian Federation
- 3 lethal cases from pandemic influenza were registered in Russia (PCR+)
Scotland
- SARI cases continue to be reported.
- Small number of B cases and H3 cases also identified.
- SARI cases continue to be reported, most of which are associated with influenza A(2009) H1N1.
Spain
- In Spain the information of severe illness due to influenza infection admitted to hospitals comes from a surveillance system developed during the 2009/2010 pandemic season for reporting severe hospitalised confirmed influenza cases.
- Since week 40/2010 and up to week 02/2011 have been reported 517 severe hospitalised confirmed influenza cases (including 24 fatal cases).
- Severely affected cases are mostly in the 15-64 age group (69%) some without underlying conditions (22%).
- Most of the severe cases and deaths have been associated with A(H1N1)2009 and have not previously been vaccinated.

(...)
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**Giuseppe** · January 21, 2011, 01:31 PM

Weekly influenza surveillance overview - 21 January 2011 (ECDC, edited): 26 H1N1(2009) flu virus were resistant to oseltamivir (3.8% of all isolates)

Weekly influenza surveillance overview - 21 January 2011 (ECDC, edited)

[Source: European Centre for Disease Prevention and Control (ECDC). Full PDF document (LINK). Extract, edited.]

SURVEILLANCE REPORT

Weekly influenza surveillance overview - 21 January 2011

Main surveillance developments in week 2/2011 (10 Jan 2011?16 Jan 2011)

This first page contains the main developments of this week and can be printed separately or together with the following more detailed information.

Most countries are now reporting regional or widespread influenza activity, with medium to very high influenza-like illness/acute respiratory infection (ILI/ARI) consultation rates and increasing trends.
This is more prominent in Western European countries.
Forty-three per cent of sentinel swabs tested positive for influenza: 74% were type A, and of the type A viruses subtyped, 99% were A(H1N1) 2009.
Since week 40/2010, 1711 severe acute respiratory infection (SARI) cases, including 73 fatal cases, have been reported by eight countries.
The number of severe influenza cases in hospital requiring intensive care is now declining in the UK but are increasing in some other countries.

Sentinel surveillance of influenza-like illness (ILI)/acute respiratory infection (ARI):

Twenty of the 27 reporting countries and the UK (England and Scotland) experienced medium or higher influenza activity intensity. Twenty three countries and the UK (England, Scotland and Wales) reported local or wider geographic spread. Twenty five countries reported stable or increasing trends.

Virological surveillance:

Sentinel physicians collected 2428 specimens, 1048 (43%) of which tested positive for influenza.

Hospital surveillance of severe acute respiratory infection (SARI):

At least 35% of the reported SARI cases were admitted to intensive care, and 16% required ventilatory support.

Sentinel surveillance (ILI/ARI) - Weekly analysis ? epidemiology

In week 2/2011, 27 countries reported on intensity of influenza activity (Table 1, Map 1).

Luxembourg reported very high intensity; Ireland and Norway reported high intensity.

Medium intensity was reported by Belgium, Bulgaria, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Italy, Lithuania, Malta, the Netherlands Portugal, Slovenia, Spain and the UK (England and Scotland).

The remaining six countries continued to report low intensity.

In week 2/2011, 27 countries reported on the geographic spread of influenza (Table 1, Map 2).

Widespread activity continued to be seen in Belgium, Denmark, Estonia, France, Ireland, Luxembourg, the Netherlands, Norway, Portugal and the UK (England, Scotland and Wales).

Regional activity was still observed in Finland, Italy and Lithuania, and now in Bulgaria, Germany and Latvia. Eight countries reported sporadic or local activity. Austria was the only country still reporting no activity.

The trend indicator was reported by 26 countries with increasing or stable trends in 25 countries. The UK (England, Scotland and Wales) reported a decreasing trend (Table 1, Map 2).

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Table 1: Epidemiological and virological overview by country, week 2/2011

[Country - Intensity - Geographic spread - Trend - No. of sentinel swabs - Dominant type - Percentage positive* - ILI per 100.000 - ARI per 100.000]

Austria - Low - No activity - Unknown (no information available) - 39 - None - 35.9 - 4.8 - 34.1
Belgium - Medium - Widespread - Stable - 74 - A - 67.6 - 441.7 - 1691.8
Bulgaria - Medium - Regional - Increasing - 13 - A(H1)2009 - 46.2 - ... - 1529.4
Cyprus - Low - Local - Stable - ... - ... - 0.0 - ...* - ...*
Czech Republic - Low - Local - Increasing - 19 - A(H1)2009 - 36.8 - 41.4 - 1017.2
Denmark - Medium - Widespread - Stable - 27 - None - 55.6 - ... - ...
Estonia - Medium - Widespread - Increasing - 59 - A(H1)2009 - 50.8 - 17.9 - 387.8
Finland - Medium - Regional - Stable - 50 - B, A(H1)2009 - 54.0 - ... - ...
France - Medium - Widespread - Stable - 157 - A(H1)2009 - 56.1 - ... - 2489.0
Germany - Medium - Regional - Increasing - 200 - A(H1)2009 - 53.5 - ... - 1179.6
Greece - Medium - Local - Stable - 14 - A(H1)2009 - 35.7 - 147.3 - ...
Hungary - Medium - Local - Increasing - 102 - A(H1)2009 - 23.5 - 184.0 - ...
Iceland - Medium - Local - Stable - ... - ... - 0.0 - 14.2 - ...
Ireland - High - Widespread - Stable - 120 - A(H1)2009 - 20.8 - 173.0 - ...
Italy - Medium - Regional - Increasing - 94 - A(H1)2009 - 41.5 - 582.3 - ...
Latvia - Low - Regional - Increasing - 0 - A(H1)2009 - 0.0 - 41.0 - 1212.2
Lithuania - Medium - Regional - Increasing - ... - ... - 0.0 - 79.6 - 712.8
Luxembourg - Very High - Widespread - Increasing - 59 - B, A(H1)2009 - 130.5 - ...* - ...*
Malta - Medium - Local - Stable - ... - ... - 0.0 - ...* - ...*
Netherlands - Medium - Widespread - Stable - 40 - A(H1)2009 - 52.5 - 70.8 - ...
Norway - High - Widespread - Stable - 15 - B - 66.7 - 181.5 - ...
Poland - ... - ... - ... - ... - ... - 0.0 - ... - ...
Portugal - Medium - Widespread - Stable - 21 - A(H1)2009 - 14.3 - 68.8 - ...
Romania - Low - Sporadic - Increasing - 51 - A(H1)2009 - 11.8 - 19.7 - 783.6
Slovakia - ... - ... - ... - 1 - None - 0.0 - ... - ...
Slovenia - Medium - Widespread - Increasing - 70 - A(H1)2009 - 58.6 - 55.3 - 1664.8
Spain - Medium - Widespread - Increasing - 522 - A(H1)2009 - 44.1 - 237.0 - ...
Sweden - Low - Sporadic - Stable - 81 - A(H1)2009 - 25.9 - 25.8 - ...
UK - England - Medium - Widespread - Decreasing - 541 - A, B - 27.7 - 66.5 - 530.4
UK - Northern Ireland - ... - ... - ... - ... - ... - 0.0 - ... - ...
UK - Scotland - Medium - Widespread - Decreasing - 59 - A(H1)2009 - 88.1 - 19.3 - 326.6
UK - Wales - Low - Widespread - Decreasing - ... - ... - 0.0 - 51.5 - ...
Europe - ... - ... - ... - 2428 - ... - 43.2 - ... - ...

*Incidence per 100 000 is not calculated for these countries as no population denominator is provided.
Note: Liechtenstein is not reporting to the European Influenza Surveillance Network

Description of the system

This surveillance is based on nationally organized sentinel networks of physicians, mostly general practitioners (GPs), covering at least 1?5% of the population in their countries. All EU/EEA Member States (except Liechtenstein) are participating. Depending on their country?s choice, each sentinel physician reports the weekly number of patients seen with influenza-like illness (ILI), acute respiratory infection (ARI) or both to a national focal point. From the national level, both numerator and denominator data are then reported to the European Surveillance System (TESSy) database. Additional semi-quantitative indicators of intensity, geographic spread and trend of influenza activity at the national level are also reported.

Virological surveillance - Weekly analysis ? virology

In week 2/2011, 23 countries reported virological data.

Sentinel physicians collected 2428 specimens, 1048 (43%) of which tested positive for influenza (Tables 1 and 2).

This represents the second decrease after the peak reached in week 52/2010 (Figure 3).

However, proportions of influenza-positive sentinel samples of more than 60% were reported by Belgium, Norway, the UK (Scotland), and Portugal, followed by proportions ≥ 50% in Denmark, Estonia, Finland, France, Germany, Greece, the Netherlands and Slovenia (Table 1).

In addition, 3623 non-sentinel source specimens (i.e. specimens collected for diagnostic purpose in hospitals) were reported positive for influenza virus.

Of the 4671 influenza viruses detected during week 2/2011, 3351 (71.7%) were type A and 1320 (28.3%) were type B.

Of the 685 sentinel influenza A viruses that were subtyped, 679 (99.1%) were A(H1N1) 2009 and six (0.9%) were A(H3) viruses (Table 2).

Since week 40/2010, 13 914 (72.5%) of the 19 177 influenza virus detections in sentinel and non-sentinel specimens, were type A and 5263 (27.5%) were type B.

Of the 3085 sentinel influenza A viruses subtyped, 2971 (96.3%) were A(H1N1) 2009, 113 (3.7%) were A(H3) and one, detected in Poland in week 50/2010, was A(H1) (Table 2).

Trends of virological detections since week 40/2010 are shown in Figures 1?3.

Since week 40/2010, 559 influenza viruses from sentinel and non-sentinel specimens have been characterised antigenically (Figure 4): 320 (57.2%) as A/California/7/2009 (H1N1)-like; 56 (10.0%) as A/Perth/16/2009 (H3N2)-like; 172 (30.8%) as B/Brisbane/60/2008-like (Victoria lineage); and 11 (2.0%) as B/Florida/4/2006-like (Yamagata lineage).

In terms of antiviral resistance, since week 40/2010, a total of 681 influenza A(H1N1) 2009 viruses and 59 influenza B viruses have been tested for neuraminidase inhibitor susceptibility .

Twenty-six (3.8%) influenza A(H1N1) 2009 viruses were resistant to oseltamivir but remained sensitive for zanamivir. All the resistant viruses carried the H275Y mutation.

Data are from single (e.g. H275Y only) or multiple location mutation analysis (full sequencing) and/or phenotypic characterisation (IC50 determination) and therefore data should be interpreted in this context.

More details on circulating viruses can be found in the December report prepared by the Community Network of Reference Laboratories (CNRL) coordination team. Also, a detailed analysis of the viruses isolated in the UK was published in Eurosurveillance indicating no evidence of any antigenic changes in the A(H1N1) 2009 and type B viruses in that country and a good match with the seasonal vaccine viruses.

In week 2/2011, 17 countries reported 1253 respiratory syncytial virus detections, a number that has decreased for the second consecutive week (Figure 5).

Table 2: Weekly and cumulative influenza virus detections by type, subtype and surveillance system, weeks 40/2010?2/2011

[Virus Type / Subtype - Current Period: Sentinel - Non-Sentinel / Season: Sentinel - Non-Sentinel]

Influenza A - 774 - 2577 / 3363 - 10551
- A(H1)2009 - 679 - 1339 / 2971 - 4834
- A (subtyping not performed) - 89 - 1210 / 278 - 5582
- A (not subtypable) - 0 - 0 / 0 - 0
- A (H3) - 6 - 28 / 113 - 135
- A (H1) - 0 - 0 / 1 - 0
Influenza B - 274 - 1045 / 1254 - 4009
Total Influenza - 1048 - 3623 / 4617 - 14560

Note: A(H1)2009, A(H3) and A(H1) includes both N-subtyped and non-N-subtyped viruses

(...)

Table 3: Antiviral resistance by influenza virus type and subtype, weeks 40/2010?2/2011

[Virus Type / Subtype - Resistance to Neuraminidase inhibitors: Oseltamivir (Isolates tested - resistant n (%) - Zanamivir (Isolates tested - resistant n (%) / Resistance to M2 inhibitors (Isolates tested - resistant n (%)]

A(H3) - ( 0 - 0 ) - ( 0 - 0 ) / ( 0 - 0 )
A(H1) - ( 0 - 0 ) - ( 0 - 0 ) / ( 0 - 0 )
A(H1)2009 - ( 681 - 26 (3.8%) ) - ( 681 - 0 ) / ( 0 - 0 )
B - ( 59 - 0 ) - ( 59 - 0 ) / ( NA* - NA* )

* NA - not applicable, as M2 inhibitors do not act against influenza B viruses

(...)

Country comments

Latvia:
- The first death cases (two) have been confirmed. Both were associated with A(H1N1)2009.
United Kingdom:
- A small number of B cases and H3 cases were also identified. Severe acute respiratory infection cases continue to be reported, most of which are associated with influenza A(2009) H1N1

Description of the system

According to the nationally defined sampling strategy, sentinel physicians take nasal or pharyngeal swabs from patients with influenza-like illness (ILI), acute respiratory infection (ARI) or both and send the specimens to influenza-specific reference laboratories for virus detection, (sub-)typing, antigenic or genetic characterisation and antiviral susceptibility testing.

For details on the current virus strains recommended by WHO for vaccine preparation click here.

Hospital surveillance ? severe acute - respiratory infection (SARI) - Weekly analysis ? SARI

Since week 40/2010, 1711 SARI cases?including 73 fatal cases?have been reported by eight countries (Table 4).

Only three countries?Belgium, Romania and Slovakia?are collecting syndromic SARI cases. The remaining countries are reporting laboratory-confirmed hospitalised influenza cases or severe influenza cases admitted to intensive care, as in Ireland and France.

During week 2/2011, 323 SARI cases were reported.

Males and females were equally affected (Table 5).

The number of SARI cases by week of onset appears to be increasing as there is a reporting delay of about two weeks (Figure 6).

However, these increases may simply reflect a new system and new countries, few of which have baselines for these data.

Of the 129 cases that tested positive for influenza reported in week 2/2011, 127 (98.4%) were infected by type A and two (1.6%) by type B viruses (Table 6). All of the 120 type A viruses subtyped were A(H1) 2009. Since week 40/2010, 922 (96.5%) of 955 influenza viruses detected were type A, and 880 (98.1%) of 897 type A viruses subtyped were A(H1) 2009.

Of the 1711 reported cases since week 40/2010, at least 710 (41.5) were admitted to intensive care with 337 (19.7%) requiring ventilatory support (Table 8).

Table 4: Cumulative number of SARI cases, weeks 40/2010?week 2/2011

[Country - Number of cases - Incidence of SARI cases per 100,000 population - Number of fatal cases reported - Incidence of fatal cases per 100,000 population - Estimated population covered]

Austria - 33 - ... - 3 - ... - ...
Belgium - 562 - ... - ... - ... - ...
Spain - 570 - ... - 24 - ... - ...
France - 289 - ... - 29 - ... - ...
Ireland - 82 - ... - 5 - ... - ...
Portugal - 79 - ... - 6 - ... - ...
Romania - 91 - 1.42 - 6 - 0.09 - 6.413.821
Slovakia - 5 - ... - ... - ... - ...
Total - 1711 - ... - 73 - ... - 6.413-821

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Table 5: Number of SARI cases by age and gender, weeks 40/2010?2/2011

[Age groups - Male - Female - Unknown]

Under 2 - 115 - 180 - 4
2-17 - 109 - 146 - 2
18-44 - 194 - 202 - ...
45-59 - 161 - 236 - 2
>=60 - 149 - 201 - 1
Unk - 3 - 6 - ...
Total - 731 - 971 - 9

Table 6: Number of SARI cases by influenza type and subtype, week 2/2011

[Virus type/subtype - Number of cases during current week - Cumulative number of cases since the start of
the season]

Influenza A - 127 - 922
- A(H1)2009 - 120 - 880
- A(subtyping not performed) - 7 - 36
- A(H1) - ... - ...
- A(H3) - ... - 6
- A(H5) - ... - ...
Influenza B - 2 - 17
Other Pathogen - ... - 33
Unknown - 67 - 739
Total - 323 - 1711

Table 7: Number of SARI cases by antiviral treatment, weeks 40/2010?2/2011

[Antiviral treatment - Number of patients who received prophylaxis - Number of patients who received anti-viral treatment]

Oseltamivir - 1 - 546
Zanamivir - ... - 10
Other (or combinations with other) - 3 - 4
Unknown - 1504 - 1072
None - 203 - 79
Total - 1711 - 1711

Table 8: Number of SARI cases by level of care and respiratory support, weeks 40/2010?2/2011

[Respiratory support - ICU - Inpatient ward - Other - Unknown]

No respiratory support available - ... - 1 - ... - ...
No respiratory support necessary - 67 - 59 - 268 - ...
Oxygen therapy - 43 - 44 - 233 - ...
Respiratory support given unknown - 263 - 15 - 256 - 114
Ventilator - 337 - 5 - 5 - 1

Table 9: Number of SARI cases by vaccination status, weeks 40/2010?2/2011

[Vaccination Status - Number Of Cases - Percentage of cases]

Both, monovalent 2009 pandemic H1N1 and seasonal 2010 vaccination - 36 - 2.1
Monovalent 2009 pandemic H1N1 vaccination - 13 - 1
Not vaccinated - 599 - 35
Seasonal 2010 vaccination - 84 - 5
Unknown - 979 - 57.2
TOTAL - 1711 - ...

(...)

Note:
Other (O) represents any underlying condition other than: asthma(ASTH), cancer(CANC), diabetes(DIAB), chronic heart disease(HEART), HIV/other immune deficiency(HIV), kidney-related conditions(KIDNEY), liver-related conditions(LIVER), chronic lung disease(LUNG), neurocognitive disorder (including seizure)(NEUROCOG), neuromuscular disorder(NEUROMUS), obesity (BMI between 30 and 40)(OBESITY), morbid obesity (BMI above 40)(OBESITYMORB), pregnancy(PREG). NONE is reported if there were no underlying conditions and UNK when the underlying conditions were unknown.

Table 10: Number of underlying conditions in SARI cases by age group, weeks 40/2010?2/2011

[Underlying condition/risk factor - 0-11 months - 1-4 years - 5y-14 - 15-24 - 25-64 - >=65]

Asthma - ... - 1 - 2 - 1 - 12 - 1
Cancer - ... - 1 - ... - ... - 7 - 2
Diabetes - ... - ... - 1 - ... - 61 - 24
Chronic heart disease - 4 - 1 - 1 - 2 - 50 - 33
HIV/other immune deficiency - ... - 3 - 1 - 3 - 45 - 21
Chronic lung disease - 2 - 1 - 1 - 2 - 36 - 19
Obesity (BMI between 30 and 40) - ... - ... - ... - 1 - 106 - 12
Pregnancy - ... - ... - ... - 8 - 45 - ...
No underlying condition - 205 - 152 - 42 - 11 - 137 - 22
Underlying condition unknown - 32 - 44 - 20 - 15 - 250 - 53
Other (including all other conditions) - 19 - 12 - 11 - 4 - 124 - 85

Table 11: Additional clinical complications in SARI cases by age group, weeks 40/2010?2/2011

[Additional clinical complications - 0-11 months - 1-4 years - 5y-14 - 15-24 - 25-64 - >=65]

Acute respiratory distress syndrome - 27 - 29 - 9 - 14 - 204 - 39
Bronchiolitis - 1 - ... - ... - ... - 1 - ...
None - 4 - 4 - ... - 5 - 22 - 9
Other (please specify separately) - ... - 2 - 1 - ... - 13 - 4
Pneumonia (secondary bacterial infection) - 15 - 28 - 7 - 15 - 317 - 73
Sepsis/Multi-organ failure - ... - ... - ... - ... - 7 - 4
Unknown - 215 - 153 - 62 - 13 - 290 - 141

Country comments

Czech Republic:
- Last week, three additional SARI cases with laboratory-confirmed pandemic strain were reported; all males (56, 57 and 60 years old) with underlying conditions.
Denmark Statens Serum Institut:
- Until 17 January 2011, a total of 39 Influenza patients have been reported by intensive care units (ICUs) in Denmark: 14 women and 25 men. The median age was 55 years (range 15?83 years).
- Of the 39 patients, 11 were newly admitted to ICU in week 2/2011.
- The number of new cases did not increase compared to last week.
- There is, however, an increasing pressure on the wards, reflected by the increasing proportion of ICU beds used for influenza patients.
- On Monday 17 January 2011 at 8:00 am, 24 influenza patients were in ICUs, corresponding with 7.5% of the total number of occupied ICU beds in the country and 13.0% in the Central Region.
- Thirty-three patients had influenza A, eleven of whom were further subtyped and had subtype H1N1.
- Six patients had influenza B.
- Four patients with influenza A died.
- Six patients were previously healthy people.
- For 26 patients one or more underlying conditions were reported. Chronic obstructive lung disease, chronic lymphatic leukemia, alcoholism, obesity and hypertension were mentioned several times. Other underlying conditions were Wegener's granulomatosis, kidney failure, asthma and immunosuppressive treatment.
- There were no pregnant women among the reported patients.
- Four patients received Extracorporeal membrane oxygenation treatment.
Ireland Health Protection Surveillance Centre:
- So far for the 2010/2011 season, 82 influenza cases have been admitted to intensive care in Ireland: 81 A(H1N1) 2009 and one A H3.
- Six influenza associated deaths have been reported to HPSC this season: 5 A(H1N1) 2009 (all admitted to ICU) and one influenza B death (not admitted to ICU).
- During week 2/2011, the number of hospitalised cases of influenza has continued to increase, with 573 cases hospitalised to date this season (as of January 19th 2011) and reports of 90 cases admitted to ICU.
- Enhanced surveillance information is available for 82 cases, 73 of whom are adults and nine are paediatric cases.
- Fifty‐two (63.4%) of the 82 cases are currently in ICU.
- Sixty of the 82 (73.1%) cases have underlying medical conditions: 54 adults and six paediatric cases.
- The underlying medical conditions include chronic respiratory disease, chronic heart disease, immunosuppression, pregnancy, metabolic disorders and morbid obesity.
- The Health Protection Surveillance Centre has been informed of six influenza associated deaths to date this season, five influenza A (H1N1) 2009 and one influenza B. One death was in a patient in the 0?4 year age group, two patients were in the 15?64 year age group and three patients were aged 65 years or older. Five deaths occurred in patients with underlying medical conditions. One death occurred in week 52/2010, one in week 1/2011 and four in week 2/2011.
- For further data and analyses, see the HSPC Report here.
The Netherlands RIVM:
- Since the start of October 2010 and as of October 20th, a total of 288 hospital admissions due to a reported laboratory-confirmed infection with influenza A (H1N1) in 2009 has taken place in the Netherlands.
- There were also 11 deaths with a laboratory-confirmed infection with influenza A(H1N1) reported.
- The number of hospital admissions due to influenza A(H1N1) in 2009 has continued to rise since last week.
- For more detail see the RIVM Report here.
Spain:
- In Spain, information on severe illness due to influenza infection admitted to hospitals comes from a surveillance system developed during the 2009/2010 pandemic season for reporting severe hospitalised confirmed influenza cases.
- Since week 40/2010 and up to week 02/2011, there have been 517 severe hospitalised confirmed influenza cases reported (including 24 fatal cases).
- Severely affected cases are mostly in the 15?64 age group (69%) some without underlying conditions (22%).
- Most of the severe cases and deaths have been associated with A (H1N1)2009 and have not previously been vaccinated.
United Kingdom:
- The number of patients in England with confirmed or suspected influenza in critical care beds have declined from a peak of nearly 800 two weeks ago (equivalent to 1.4 per 105 population) to around 400cases on January 20 2011.
- Over 80% of these are in the 16?64 year age group.
- For further information, click here.
- Up until 19 January 2011, 254 fatal influenza cases from across the UK were reported to the HPA, including 165 cases from England.
- Further epidemiological information on cases is available on 214 of these cases.
- One hundred and ninety-five (91%) of these cases were associated with H1N1 (2009) infection, three with untyped influenza A and 16 (7%) with influenza B infection.
- Reported deaths have been mainly in younger adults and children.
- Among the 210 cases with information on age, seven (3%) have been younger than 5 years, 11 (5%) in the 5?14 year age group, 137 (65%) from 15 to 64 years and 55 (26%) were older than 64 years of age.
- One hundred and twenty-eight of 159 fatal cases with available information (81%) were in one of the clinical risk groups for vaccination, which includes pregnant women.
- The leading reported clinical risk factors for those with information were underlying respiratory disease, including asthma (n=29) and neurological disease (n=15).
- Conversely, 19% of the deaths were in healthy people outside these risk groups (click here for report).
- For further information, click here.

The report text was written by an editorial team at the European Centre for Disease Prevention and Control (ECDC): Eeva Broberg, Flaviu Plata, Phillip Zucs and Ren? Snacken. The bulletin text was reviewed by the Community Network of Reference Laboratories for Human Influenza in Europe (CNRL) coordination team: Adam Meijer, Rod Daniels, John McCauley and Maria Zambon. On behalf of the EISN members the bulletin text was reviewed by Bianca Snijders (RIVM Bilthoven, The Netherlands) and Thedi Ziegler (National Institute for Health and Welfare, Finland)

Maps and commentary used in this Weekly Influenza Surveillance Overview (WISO) do not imply any opinions whatsoever of ECDC or its partners on the legal status of the countries and territories shown or concerning their borders.

All data published in the WISO are up-to-date on the day of publication. Past this date, however, published data should not be used for longitudinal comparisons as countries tend to retrospectively update their numbers in the database.

? European Centre for Disease Prevention and Control, Stockholm, 2010

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**Giuseppe** · January 25, 2011, 11:12 AM

ECDC News - Influenza progresses in Europe: there is still time to take preventive measures against it (ECDC, Jan 25 2011, edited)

ECDC News - Influenza progresses in Europe: there is still time to take preventive measures against it (ECDC, Jan 25 2011, edited)

[Source: European Centre for Disease Prevention and Control (ECDC), full page: <cite cite="http://www.ecdc.europa.eu/en/press/news/Lists/News/ECDC_DispForm.aspx?List=32e43ee8%2De230%2D4424%2Da 783%2D85742124029a&ID=413&RootFolder=%2Fen%2Fpress %2Fnews%2FLists%2FNews">News - Influenza progresses in Europe: there is...</cite>. Edited.]

Influenza progresses in Europe: there is still time to take preventive measures against it

25 Jan 2011

Risk assessment on influenza 2010-2011

ECDC - Today, the European Centre for Disease Prevention and Control (ECDC) published its initial Risk Assessment on this season?s influenza in Europe.

The report analyses the main features, risks to human health and likely course of the 2010/2011 influenza season in Europe.

This is an especially important season as it is the first one after the pandemic.

This year, while most people experienced a mild disease when infected, a significant number of deaths and severe cases have been reported in association with influenza in the first affected countries.

In England, the peak was reached when, in one single day, for every 100,000 citizens, 1.4 were hospitalised in intensive care units suffering from influenza.

In Ireland, the peak was reached when of every 100,000 citizens, 1.1 were hospitalised in intensive care units in one day.

The Risk Assessment identifies important differences between the current and past influenza seasons.

People in the clinical risk groups defined at national level, which for this influenza season are predominantly people with underlying medical conditions and pregnant women, are being particularly affected by more severe ill-health and premature deaths as a result of influenza.

However, surveys undertaken by the Member States and ECDC indicate that many of those at highest risk across Europe have not yet been vaccinated.

ECDC Director Marc Sprenger stressed:

?Even in the middle of the influenza season, many preventable severe influenza cases and fatalities can still be avoided through vaccination. Therefore, it is extremely important that people in the risk groups who have not already been vaccinated seek the advice of their national authorities about influenza prevention. Being more vigilant over personal hygiene measures, such as washing hands frequently or avoiding touching the eyes, nose and mouth are also very useful strategies in preventing the spread of influenza infection?.

The good news is that both the seasonal and pandemic influenza vaccines are working very well in preventing infection and premature deaths.

ECDC?s Risk Assessment highlights the multiple scientific studies that indicate seasonal influenza vaccines are effective and very safe.

ECDC has now confirmed through a study recently conducted in seven EU Member States that the pandemic influenza vaccine can provide up to 80% protection against the pandemic influenza strain, which continues to be the most important cause of severe influenza this season.

According to the study, protection against the pandemic influenza strain is provided as soon as one week after vaccination.

Related links:

1) Vaccine European New Integrated Collaboration Effort (VENICE) project
2) Valenciano M Kissling E, Cohen J-M, Oroszi B, Barret AS, Rizzo C et al Estimates of Pandemic Influenza Vaccine Effectiveness in Europe, 2009?2010: Results of Influenza Monitoring Vaccine Effectiveness in Europe (I-MOVE) Multicentre Case-Control Study. Plos Medicine PLoS Med 8(1): e1000388. doi:10.1371/ journal.pmed.1000388 (Published 11-01-2011).

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**Giuseppe** · January 25, 2011, 11:58 AM

Seasonal influenza 2010?2011 in Europe (EU/EEA countries) - January 2011 (ECDC, extract, edited)

Seasonal influenza 2010?2011 in Europe (EU/EEA countries) - January 2011 (ECDC, extract, edited)

[Source: European Centre for Disease Prevention and Control (ECDC), full PDF document (LINK). Extract, edited.]

ECDC FORWARD LOOK RISK ASSESSMENT

Seasonal influenza 2010?2011 in Europe (EU/EEA countries) - January 2011

Executive summary

The 2010/11 seasonal influenza epidemics in Europe are dominated so far by the A(H1N1)2009 viruses which emerged in the 2009 pandemic, although these are now considered seasonal viruses.

There are also some B viruses circulating.

Both are causing some severe disease and premature deaths but the preliminary data indicate that 90% of the fatalities are due to A(H1N1)2009

This is the first European influenza season after the 2009 pandemic.

Many of the features and required countermeasures are the same as for the previous seasonal influenzas (which ran until the 2008/09 season).

However, there are important differences which Europe needs to take into consideration, notably the type of people who are most affected and experiencing severe disease.

In the first affected country (the United Kingdom) there have been higher numbers of people seeking care than on average with seasonal influenza.

Also, the number of people with severe disease has been considerably higher than during the pandemic with at its peak 1.4 persons/105 population requiring higher level (intensive) hospital care at one time.

The reason for the latter finding is unclear.

Part of the reason for the increased demand in primary care has been persons seeking immunisation or treatment as information on the severe cases became apparent to the public.

These phenomena have also been observed in other countries in Western Europe, albeit at lower levels.

A broad pattern of west to east progression of influenza epidemics is underway, such as has been seen in previous years.

Hence the experience of the Western countries can inform those further to the east of the European Union.

All these considerations constitute the justification for this Interim ECDC Risk Assessment, which will be updated at intervals.

Those mostly reported as experiencing severe disease or dying prematurely are those adults below the age of 65 years and children in the clinical risk groups.

These constitute over 80% of cases reported.

Severe disease also affects some pregnant women.

There are also some previously entirely healthy people, who account for 20% of the deaths in the UK, and higher percentages requiring higher-level (intensive) hospital care in France.

As in the pandemic, there have been some older people experiencing severe disease but reported cases have been low in numbers.

Numbers of severely ill cases requiring care are now declining in the UK but they are rising in other countries.

It cannot be anticipated whether those countries will experience the same rates as the UK.

The circulating viruses have not as yet changed or mutated, and it is expected that the seasonal vaccines will be effective in preventing disease.

ECDC-coordinated studies in the pandemic found up to 80% effectiveness for vaccines containing A(H1N1)2009.

Other observational studies have confirmed this.

Indeed there are encouraging data suggesting that significant protection develops within a week of immunisation. Data on the early deaths in the UK indicate that the vaccines in use are also effective in preventing influenza-related deaths.

Recent surveys of pandemic and seasonal vaccine coverage by Member States indicate that there are many people in the clinical risk groups in Europe who remain unvaccinated, either with the pandemic vaccine or the 2010 seasonal vaccine.

In the UK, there is a rise in laboratory reports of two or more severe invasive bacterial diseases; pneumococcal disease and group A streptococcal disease has been observed.

Rates of invasive streptococcal disease rose to 0.33/105 population in December 2010 compared to 0.19/105 in an average year.

To date, this has not been reported elsewhere in Europe. It is unclear whether this rise is associated with the influenza epidemics and contributing to the high numbers of severe cases in the UK, but that is a possibility.

The scientific evidence to date provides justification for the following countermeasures already adopted by some countries in addition to the usual influenza personal protective measures (early self isolation, respiratory hygiene and hand-washing):

Continued vaccination of all those recommended for vaccination following national guidelines but especially clinical risk groups, including pregnant women, especially as it seems that the vaccine provides some protection even just a week after injection. However, there may be vaccine availability, logistical and administrative issues that will make this difficult in some settings.
Use of antiviral treatment in those presenting with severe influenza-like illness, pending virological confirmation, and in those with risk factors with milder disease.
Alerting higher level healthcare services of potential increased numbers of influenza patients this winter, potentially already in the next few weeks.
Advising clinicians to be vigilant to the possibility of severe illness due to bacterial co-infection with influenza, including invasive group A streptococcal, pneumococcal and meningococcal infection, and to be aware of the possibility of such bacterial co-infection in people with flu-like illness.
Use or creation of clinical networks for surveillance, evaluation and sharing of clinical experience.

This is an interim risk assessment and will be up-dated at intervals as more data and analyses emerge.

Source, and type of request

ECDC internal decision: urgent; replacing a previous internal threat assessment.

Questions

Main questions

What are the main features, risks to human health and likely course of the 2010/2011 influenza season in Europe and how likely is it that the initial experience in the first affected countries will be replicated in other EU/EEA countries in terms of a) the pattern of infection and b) the impact on the health services?

What possible countermeasures and actions do the scientific and public health data and analyses support being taken by authorities?

More specific questions

Why have a number of community and hospital indicators of influenza activity risen to levels higher than that seen in the 2009 pandemic despite the same virus (AH1N1)2009 being seen to be the main driver in both?
Can changes in the viral mix be anticipated later this season?
Has there been any change in the virology of the A(H1N1)2009 virus?
Has there been any emergence of antiviral resistance?
What is likely to be the effectiveness of influenza vaccines and antivirals?
Is the observation of increased incidence of two types of invasive bacterial infections in the UK likely to be related to influenza?
Is an observed rise in all-cause/all-age mortality observed in a number of the Western European countries likely to be related to influenza?

Consulted experts

Internal to ECDC: Epidemic intelligence, influenza and communication functions.

Specific contributions from: Bruno Ciancio, Eeva Broberg, Kari Johansen, Angus Nicoll (guarantor) and Pasi Penttinen.

External to ECDC:

Preben Aavitsland, Norwegian Institute of Public Health (FHI), Oslo, Norway
Caroline Brown, World Health Organization (WHO) Regional Office for Europe, Copenhagen, Denmark
Bruno Lina, University of Lyon and National Influenza Centre (Southern France), Lyon, France
Marianne van der Sande, National Institute for Public Health and the Environment (RIVM), Bilthoven, Netherlands
John Watson, Health Protection Agency (HPA), London, UK

ECDC is very grateful for the expert input from the persons above. They were consulted as individuals on the basis of their expert knowledge and experience rather than as representatives of their institutions or countries. It should also be noted that responsibility for the Risk Assessment is with ECDC rather than with these individuals, and that this Risk Assessment will be updated frequently.

Evidence accessed

Global and European Data and Analyses

WHO. Influenza update ? 14 January 2011, available from: National data from EU/EEA Member States as reported to ECDC and appearing in the (LINK)
Weekly Influenza Surveillance Overviews (WISO), Week 2, 21 January 2011.
CNRL-ECDC Influenza virus characterisation, Dec 2010, available from: (LINK)
EUROMOMO ? European monitoring of excess mortality for public health action. Pooled results are available from: (LINK)

More specific and detailed data from selected western EU/EEA countries

France: Institute de Veille Sanitaire;
Ireland: Health Protection Surveillance Centre;
Netherlands: RIVM ?Griep en verkoudheid? (influenza and colds);
Norway: Public Health Institute (specifically a risk assessment and forecast, 11 January 2011 ? English translation);
UK: Health Protection Agency (HPA) ? National Influenza Weekly Reports (specifically Week 2, 12 January 2011 and other information for health professionals;
UK: Department of Health, ?Winterwatch? health data, 20 January 2011.

Regional and national influenza websites in temperate northern hemisphere countries

WHO Regional Office for Europe (Euroflu Elecronic Bulletin),
Canada (PHAC-Fluwatch),
China (CCDC),
Japan (NIID),
USA (CDC-FluView),
EUROMOMO European Mortality Project (Weekly mortality bulletin)

See also references below.

Risk assessment

Epidemiological situation and impact on the health services

EU/EEA countries. See latest Weekly Influenza Surveillance Overview (WISO) Increasing levels of influenza transmission have been reported in the majority of EU/and EEA countries.

The first country to report increases in consultations was the UK in week 47/2010.

As of week 1/2011, 17 EU/EEA countries participating in the European Influenza Surveillance Network (EISN) (Belgium, Bulgaria, Denmark, Estonia, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovenia, and Spain) were reporting increasing primary care consultations, influenza-like illness and/or acute respiratory infections (ILI/ARI) above baseline levels.

As of week 2, the first country that reported rises, the United Kingdom, was now reporting a downward trend and a number of other countries reported that their levels were now unchanging (?stable?), albeit at high levels (WISO, week 2).

The highest incidence of consultations for ILI/ARI has been observed among individuals below 65 years of age. .

Looking over time, and taking into account the effect of the Christmas and New Year holiday period on transmission and reporting, there is a broad pattern of west to east progression across Europe, such as has been seen in many but not all previous years (1).

There are a number of reports of severe cases from individual countries with over 1700 cases of hospitalised severe acute respiratory infections (SARI) as of week 2 reported to ECDC from eight countries (Austria, Belgium, France, Ireland, Portugal, Romania, Slovakia and Spain).

In addition there are analyses on national web sites on a number of countries, notably France, the Netherlands and Norway.

In Ireland as of the latest surveillance report (Week 2/2011)(29) there were 52 cases requiring higher level (intensive) care. This is equivalent to 1.2/105 population, while rates have been lower in the Netherlands.

However, all these analyses are difficult to interpret since such reporting is either new or was only introduced from the pandemic (2009) onwards and hence knowledge of baselines (what is normally experienced) is limited. Similarly, there was previously no report of impact on health services.

It was fortunate that the UK has experienced some of the first effects of this year?s epidemics since it has one of the more developed and timely surveillance systems worldwide.

Key entry points to the results of these are the Health Protection Agency?s National Influenza Weekly Reports, the Department of Health?s (England) Winterwatch and their equivalents in the so-called devolved administrations1.

In the UK the rises in community consultations were preceded by the detection of severe cases of influenza, an increase in ITU-bed occupancy and use of ECMO facilities when rates of consultations with influenza-like illness (ILI) or acute respiratory infections (ARI) were still low.

This led to the UK alerting the rest of Europe.

A similar phenomenon was seen in the Netherlands (see RIVM ?Griep en verkoudheid? (influenza and colds) website).

This pattern of severe cases preceding obvious community epidemics might be considered unusual, though the early impact of influenza epidemics on secondary care has not been well described in any country.

Subsequently in the UK, community indicators (e.g. calls to help lines) and levels of consultation in primary care rose steeply to higher levels than seen in any winter since the intense A(H3N2) winter epidemics of 1999/2000.

Equivalent levels of consultations were experienced in the spring/summer wave of 2009 in England and Wales, but that was a period of intense awareness, case finding and care seeking.

Trends and comparisons of consultations rates for illnesses that might be influenza (ILI/ARI) have to be interpreted with care as they are very sensitive to awareness by the public and doctors and media information. As a consequence, more patients with mild symptoms consult who might significantly even within a season (30).

Subsequently in the UK, community indicators have started to decline.

Within this national pattern there have been some important regional differences as there were during the pandemic but it is not yet clear whether places that were more affected in 2009 are less affected now, as was observed in New Zealand (see below).

On 6 January 2011, there were nearly 800 patients with confirmed or suspected influenza in higher-level care (NHS critical-care beds) in England. This was equivalent to 1.4/105 population and about 20% of capacity. The latter percentage statistic needs to be interpreted in the context of the national higher-level care (intensive care) capacity which varies considerably in Europe (2).

As of 20 January, this prevalence of cases requiring care had declined to around 400 cases (see Department of Health (England) Winterwatch, 20 January 2011).

The characteristics of these patients seemed similar to that seen in the pandemic and different to the prior seasonal epidemics.

More than 80% of patients were below the age of 65 years.

This caused some disruption to higher-level care services in some parts of the UK and led to cancellation of elective surgery, with hospitals adopting plans for dealing with increased pressures.

These rates (severe influenza cases per 105 population) were considerably higher than what was experienced in the 2009 pandemic.

The reasons for this are not clear at present but it could be because there were both A(H1N1)2009, B and other viruses circulating, or that in the pandemic, transmission in the UK was extended over a number of months, interrupted by the closure of schools in the summer (3), while now transmission is being condensed into the usual few weeks of winter epidemics (4).

In addition in 2010/11 transmission is happening in the winter when incidence of other infections (including that by potentially invasive bacteria) is more common, and so this may also be increasing.

No other country is reporting the volume of severely ill influenza patients that have been seen in the UK intensive care units.

However, there are specific reports of numbers of severe influenza cases, cases requiring intensive care, and deaths from Denmark, France, Ireland, and the Netherlands.

In addition, six other countries (Austria, Belgium, Spain, Portugal, Romania, and Slovakia) as well as France and Belgium are reporting SARI cases to ECDC (see below for more detail). In a French hospital, the sentinel reporting system indicated that around 40% of people needing higher-level care were previously healthy and outside the risk groups (31).

The increase cannot be explained by any reduction in vaccination coverage rates in the UK.

As of week 2/2011, seasonal vaccination coverage in England was reported to be little different from what was seen in 2008 and 2009, especially in the most important population: people in clinical risk groups (5) cases (see Department of Health (England) Winterwatch, 20 January 2011).

Table 1. Interim vaccine coverage in the UK (England) in 2010 compared to previous years

[Vaccine - Older people - Clinical risk group under 65 years]

Pandemic vaccination 2009 (14) - Not targeted - 37.6%
Seasonal vaccine (as of week 2/2011 (1))
- 2009 - 74% / 2009 - 46%
- 2010 - 72% / 2010 - 51%
- 2011 - 72% / 2011 - 48%

Characteristics of the deaths ? UK and elsewhere.

As of 20 January 2011, more that 250 premature deaths identified to be associated with influenza this season have been reported to the HPA.

Around 80% have been people in risk groups (including those for pandemic and seasonal influenza) under the age of 65 years.

Conversely, around 20% of deaths have been among previously healthy people.

Only 26% have been over 64 years of age.

Most cases (over 90%) have been associated with influenza A(H1N1)2009 but for about 7% the association is with influenza B viruses.

All the viral isolates from severe cases that have been subtyped are matched well by the seasonal influenza vaccine (1,8).

Clinical anecdotes from the UK indicate that the severe disease in adults is mostly acute respiratory distress syndrome and invasive bacterial disease.

However there is reason for caution since it should not be assumed that there is no influenza-related premature mortality taking place in older people aged over 65 years.

Apart from the UK, there is currently only limited information on the incidence and character of severe acute respiratory infections, mortality, case fatality rate, and risk factors for severe illness in Europe in 2010/11.

However, some countries are reporting this now (see latest Weekly Influenza Surveillance Overview (WISO) ECDC has asked all countries both for data from sentinel reporting of Severe Acute Respiratory Infections (SARI), and in addition for data from intensive care units.

A number of countries (Austria, Belgium, Spain, France, Portugal, Romania, and Slovakia) are making this available to ECDC. Reports from other European countries (Ireland, Netherlands, and France) conform to a similar pattern for deaths or severe disease. ).

All-cause deaths.

In England and Wales (UK), the Netherlands and some other countries in Western Europe, all-cause/all-age deaths rose above the expected normal upper level for the time of year.

In England and Wales, this occurred for a number of four consecutive weeks (49?51).

However, only a proportion of this will be attributable to influenza, and that proportion could be quite small (1).

Other contributions will be from other respiratory infections and the cold weather over the Christmas period.

During the pandemic, there were only changes in all-cause mortality in some age-specific groups (6). However, in other years, increases in all-cause/all-age mortality occur regularly in winter. The last occasion being the bad A(H3N2) winter of 2008/09

The EUROMOMO pilot project monitors age-specific mortality rates for a collection of seven EU/EFTA countries2.

Individual country data are then put together and reported as pooled results on the EUROMOMO website.

Unlike in the UK and the Netherlands, no rises were initially seen in the rates this winter as of week 2. However, it needs to be kept in mind that the countries involved were at an earlier stage of their winter epidemics than the UK (K Mobak, personal communication to ECDC).

A rise in some invasive bacterial infections ? UK.

In the UK, routine laboratory reporting has found recent increases in two or three of the four routinely and commonly reported invasive bacterial infections in England.

These are pneumococcal infections and invasive group A streptococcal infection (iGAS).

Meningococcal infections have also increased but only to a level which was seen in 2008 ? after a very low year in 2009.

There has been no rise in invasive staphylococcal disease.

All these infections may occur as co-infections with influenza.

The broad age groups from which the invasive specimens are obtained are the same as for severe influenza disease.

The rise in reports of invasive group A streptococcal (IGAS) infection is above levels observed in previous winters (see UK HPA website: Group A streptococcal infections: seasonal activity 2010/11).

Numbers of invasive streptococcal disease rose to 185 (a rate of 0.33/105 population) in December 2010 compared with 106 (0.19/105) on average for the years from 2002 to 2008, and an annual range of 80 to 157 reports.

However, it is unclear whether there is an association with influenza, and it needs to be seen whether there are any similar findings in other countries (7).

An earlier observational analysis in the pandemic period found that early use of oseltamivir was associated with a reduced risk of invasive bacterial disease (28), which in turn is consistent with a recent re-analysis of an earlier controversial meta-analysis by Kaiser et al (8,9).

Further investigations are underway in the UK, but the rise was sufficient to elicit an alert to be issued by the authorities to all doctors to be on the look-out for these infections and to treat them early (UK Chief Medical Officer Alert, 10 January 2010).

Virological situation in the EU/EEA

See latest Weekly Influenza Surveillance Overview (WISO) ? Week 2 2011 .

Among specimens collected by sentinel physicians participating in EISN, the percentage that tested positive for influenza was 43% in week 2/2011.

For combined sentinel and non-sentinel influenza positive specimens, 72% were type A and 28% were type B. Ninety-nine per cent of sub-typed influenza A viruses were A(H1N1)2009. However, there was some variation from country to country. For example France has been experiencing more B viruses than Europe overall. France (INVS) and Norway (Public Health Institute) are seeing mostly influenza B viruses.

Overall respiratory syncytial virus (RSV) detections in countries reporting to ECDC started to rise during week 44/2010 were highest during week 51/2010, but have since declined.

Since week 40/2010, 559 influenza viruses from sentinel and non-sentinel specimens have been characterised antigenically: 320 (57.2%) as A/California/7/2009 (H1N1)-like; 56 (10.0%) as A/Perth/16/2009 (H3N2)-like; 172 (30.8%) as B/Brisbane /60/2008-like (Victoria lineage); and 11 (2.0%) as B/Florida/4/2006-like (Yamagata lineage).

Antiviral resistance and use of antivirals.

Since week 40/2010 in the EISN system, a total of 185 influenza A(H1N1)2009 viruses and six influenza B viruses have been tested for susceptibility to neuraminidase inhibitors.

Data were provided for either single location (e.g. H275Y only) or multiple location substitution analysis (full sequencing) and/or phenotyping (IC50 determination) and should be interpreted in this context.

All but two viruses out of 185 were sensitive to both oseltamivir and zanamivir.

Two A(H1N1)2009 viruses from the UK had the H275Y substitution known to confer resistance to oseltamivir while retaining susceptibility to zanamivir.

Both viruses were from patients who had not been known to have been treated with oseltamivir.

There are additional reports of antiviral resistance from the UK that have yet to enter the EISN system.

In its 20 January report, the UK?s Health Protection Agency included details of influenza A(H1N1)2009 viruses that had been tested for antiviral susceptibility since week 40/2010. 27 have been found to carry the H275Y mutation, which confers resistance to the antiviral drug oseltamivir.

Fifty-one H1N1 (2009) viruses have been fully tested for susceptibility, one of which was found to be phenotypically resistant to oseltamivir (included in the 17), while all 51 retained sensitivity to zanamivir.

In addition, three influenza A(H3) viruses and fifty-eight influenza B viruses have been fully tested for susceptibility and found to be sensitive to oseltamivir and zanamivir.

Further investigations are underway to determine what proportion of the individuals have been prescribed oseltamivir.

At least a proportion of these have been from individuals known not to have received antivirals, which means there are a least some freely transmitting A(H1N1)2009 viruses circulating.

There has been considerable use of, and demand for, this treatment in the UK since awareness rose concerning the severe cases.

Following the observation of these cases, the UK authorities encouraged the use of antivirals for early treatment, initially of those with disease in the risk groups.

When it became apparent that there was a substantial proportion of severe cases and deaths in healthy individuals, doctors were given more freedom to use their discretion on whom to treat (see HPA website, Information for health professionals.

The amount of antivirals used cannot readily be quantified, but a release from a national antiviral stockpile was necessary to supplement pharmacy supplies.

Viruses from the first fatal cases in the UK have been analysed and the results published (10).

No unique mutations have been associated with severe or fatal cases of influenza A(H1N1)2009.

The genetic drift that has taken place has been as expected (gradual natural viral evolution). Further comprehensive analyses are underway (8).

(...)

International virological picture

WHO (Influenza Update ? 14 January 2011);
WHO Regional Office for Europe (Euroflu Weekly Electronic Bulletin, Week 1, 14 January 2011),
Canada (PHAC-Fluwatch),
China (CCDC),
Japan (NIID),
USA (CDC-FluView),
EUROMOMO European Mortality Project (Weekly mortality bulletin)

The influenza virus mix observed in the EU/EEA countries has been different from that in North America and northern China, where reports show an influenza season dominated by A(H3N2) and B viruses. Most recently though there has been a report of increasing proportions of A(H1N1) in Japan and South Korea ,though not in northern China (southern China has more of an equatorial pattern of influenza transmission) (WHO Report, 14 January).

No reports of significant impact on health services have come to WHO at regional or global level equivalent to that which has been seen in the UK.

However, it has to be kept in mind that reporting of impact on health services is relatively new and difficult to interpret (see WHO Influenza update ? 30 December 2010).

Likely immunity to circulating viruses: natural and acquired immunity ? serosurveys

There are limited contemporary seroepidemiologial data published and only for A(H1N1)2009 antibodies for a few countries (Finland, Norway, UK)

Hence a comprehensive serological analysis for European vulnerability is not possible.

Also some of the results are confusing or difficult to interpret.

For example in Norway in the over-70 year age group there were only about 10% of persons with antibodies to A(H1N1)2009 before the pandemic(11). However there were very few cases in that age group in Norway (Norway: risk assessment). Clearly there is more to immunity to influenza than is reflected in simple influenza antibody seroprevalence surveys.

Some idea of the duration of anti-body based immunity may also be inferred from the Norwegian serosurveys where population seroprevalences (HAI >= 20) of 7 %, 59 % and 45 % were found for August 2009, January 2010 and August 2010, respectively (the figures for HAI >=40 were 3%, 45 % and 26%) (Norway: risk assessment). This indicates some sustained duration of protection is likely at this time.

An international review by WHO after the 2009 pandemic suggested that between 5% and 60% of populations in different continents across the age groups had antibodies against the A(H1N1)2009 virus.

The seropositivity was highest in children and teenagers (20-60%) as well as in the elderly older than 80 years (20-40%).

Pre-existing or cross-reactive antibodies against the virus are present mostly in sera of older people born before the late 1950s that could have encountered the 1918 pandemic influenza A(H1N1) virus(12).

These data remain difficult to interpret for a number of reasons, different in testing methods and standards and whether the presence of antibodies excludes other non-humoral protection, such as cell-based immunity.

However one important point is that the second round of serology in the UK indicated enough susceptibility to support the observed transmission(13).

Vaccine coverage

Further information relevant to particular vulnerabilities in Europe can be inferred from the coverage of seasonal and pandemic vaccines, especially among the risk groups experiencing severe illness this season.

Seasonal influenza vaccines in use include antigens for the A(H1N1)2009 influenza virus, A(H3N2) and a B virus.

Seasonal influenza vaccination coverage in risk groups in EU/EEA countries has been variable in earlier years and such variability can be expected to be present also during the current 2010/11 season (see Figure 1 for older people).

Coverage among the people in the clinical risk groups is less well known but where data are available it is always lower than in older people in the same countries.(14-15)

The current coverage rates in Europe for the new trivalent seasonal vaccine will not be known ahead of the annual VENICE survey later this year except for some countries that can report in season such as the UK where the coverage rates held up well (see above).

However, given the poor experience with pandemic vaccination in some other countries (Figure 3) and controversy over even the need for pandemic vaccination, it may be that coverage may not be as good in 2010 as in previous years.

Given that the coverage in the clinical risk groups is usually below 50% in countries that can measure this, it is most likely that there are many people in these groups in Europe that did not receive the new seasonal vaccine in 2010.

Pandemic vaccine A(H1N1)2009 coverage rates among Member States in the EU were highly variable, ranging from zero to over 60% of the population (see Figures 2 and 3) (14).

This indicates that there are four Nordic countries that could have significant population protection against A(H1N1)2009, especially when naturally acquired infection is added in. It is not yet established how enduring the protection is conferred by pandemic vaccination.

Similarly it is unclear whether the herd immunity though vaccination, natural and acquired immunity will be sufficient to reduce transmission compared to what is seen in countries which took the approach of protecting those most at risk.

However countries with overall low coverage of clinical risk groups will seem more likely to experience higher numbers of severely ill patients than those with higher coverage. This seems to be especially likely given the high effectiveness of the pandemic vaccine in preventing infection (see below).

(...)

These data suggest that unless there has been very widespread infection (which is not supported by the serological data) there are many vulnerable people out there in Europe.

Impact on health services

As yet the UK has a unique experience in terms of both pressures in primary care, hospital pressures and impact on all- cause/all-age mortality (though that certainly will not just reflect influenza potential: additional factors contributing to this excess include recent cold weather and other circulating respiratory viruses(2)).

The main pressure has been on the hospitals, and they have coped, albeit with some use of emergency plans. Although primary care consultation rates have risen, they are reported to be manageable. Other EU countries have reported growing pressure on intensive care (France, the Netherlands and Denmark) but nothing that cannot be managed, and overall pressure is less than in the UK.

The southern hemisphere experience

Looking to the southern hemisphere countries and the winter they experienced in mid-2010, the most obvious similarities are to New Zealand which uniquely had a winter entirely dominated by A(H1N1)2009, though its level of hospital activity was less than in its pandemic winter (2009) (16).

A notable comment from the New Zealand winter was that ? although overall the numbers of severely ill cases were lower than in the pandemic winter of 2009 ? there were regional and local differences, with a tendency for places that were affected less in the 2009 winter to be more affected in 2010 (32).

The southern hemisphere experience in 2010 (the first winter with seasonal influenza after the pandemic) was variable. Both Chile and Australia experienced later epidemics of A(H3N2) and B viruses, following initial transmission of A(H1N1)2009, so that should be considered a possibility for Europe (16).

Likely effectiveness of countermeasures including vaccination and antivirals

There is no reason to expect that the normal trio of personal countermeasures (early self-isolation of those with symptoms, respiratory hygiene, and regular hand-washing) will be any more or less effective this season (see ECDC health information: Personal protective measures for reducing the risk of acquiring or transmitting human influenza and WHO).

Equally, the usual immunisation of healthcare staff and infection control measures (stringent measures including mask wearing, according to national and local guidance) will be important in some healthcare settings.

According to the antigenic characterisation data available through the EISN and data recently published in Eurosurveillance, the influenza A(H1N1)2009, which is currently circulating in Europe, is antigenically homogeneous and similar to the A(H1N1)2009 virus included in the 2010/11 seasonal influenza vaccine (10), i.e. the vaccine and the circulating virus match well.

Estimates of pandemic vaccine effectiveness in Europe showed good protection conferred by the vaccine, as would be expected when a good match is present between the vaccine strain and the circulating virus. Estimates of vaccine effectiveness from field epidemiology varied by age and risk group, but were all above 70% (17-20)(21-22). An especially important finding is that some protection was apparent even a week after vaccination. These studies, with the exception of a small study done in in Castell?n, Spain (21), mostly had mild influenza illness as the endpoint.

An important factor for analysis is the vaccination history among those with severe disease or those who have died from influenza.

This is being looked at first in the UK. As of week 3, a report by the HPA of fatal cases with available information on immunisation history states that 59 of 71 (83%) cases had not received 2010/11 trivalent influenza vaccine this season.

Thirty-eight of 40 cases with available information had not received monovalent pandemic influenza vaccination last season.

This is much less than what would be expected by chance, given the reported coverage of vaccination in the clinical risk groups with the pandemic and seasonal vaccines in 2009 and 2010 respectively (Table 1).

Hence these findings are compatible with results that describe the vaccines as protecting against fatal outcome as well as mild disease.

Studies to estimate vaccine effectiveness for the 2010/11 trivalent vaccines are currently ongoing in eleven EU countries as part of the I-MOVE collaboration.

Preliminary results from a large I-MOVE cohort study involving 152 581 individuals (2010/11 seasonal vaccine coverage: 34%) in one region of Spain shows good protection against medically attended ILI and ILI (confirmed as influenza induced) by the 2010/11 vaccine during the period week 43/2010 and week 2/2011 (Dr Jes?s Castilla, personal communication to ECDC, January 2011).

Although having received pandemic vaccine last season is expected to provide some protection against the currently circulating A(H1N1)2009 virus, there is no precise estimate on how effective previous pandemic vaccination will be in protecting individuals in different age and risk groups or what effect it might have on transmission.

There are a number of observations from the pandemic indicating that early use of antivirals was associated with a better outcome in people with influenza disease due to A(H1N1)2009 than people who did not receive antivirals or received them later (23,24).

Though even late application was associated with improved survival and less likelihood of admission to an ITU (24,25). Also, a formal re-analysis of an earlier and latterly controversial meta-analysis of trial data by an independent group has essentially reproduced the earlier findings (8,9).

Safety of interventions

There is no indication of any Adverse Event Following Immunisation (AEFI) safety signal related to the 2010/11 trivalent seasonal influenza vaccines being used in EU.

For the monovalent 2009 pandemic vaccines )which are currently hardly being used in the EU apart from in the UK), multicountry investigations of two signals associated with the pandemic vaccine are underway concerning Guillain-Barr? Syndrome (GBS) and narcolepsy in children.

The results of the GBS study are reassuring (they are yet to be published). Work on a narcolepsy signal is underway. This is almost entirely involving children immunised with one product. The signal is predominately from two Nordic countries (Finland and Sweden). A preliminary review on the narcolepsy signal undertaken by the European Committee for Medicinal Products for Human Use (CHMP) under the European Medicines Agency concluded there was no convincing evidence of additional risk at this stage though additional research was needed (33). Such work is underway, funded by ECDC. There have been no convincing adverse event signals reported for the neuraminidase inhibitors the antivirals used in Europe (34).

ECDC scientific and public health advice

What countermeasures do these scientific and public health data and analyses support?

Vaccination. Since there are many people unvaccinated in the clinical risk groups, there will be advantages to continuing vaccination particularly for these persons. This seems especially advantageous in view of findings:

that the A(H1N1)2009 vaccines are effective and very safe;
that they protect against fatal disease outcome as well as mild disease; and
that protection starts in as short a period as a week after vaccination.

It also should be recognised that there may be vaccine availability, logistical and administrative issues that make implementation of this policy difficult in some settings.

Antivirals.

The available data support the early use of antiviral treatment in all those presenting with severe influenza-like illness pending virological confirmation, and in those with risk factors with milder disease.

The occurrence of severe disease and even deaths in entirely healthy adults and children poses a problem. If it was felt that all people with early infection should be treated, the amount of antivirals that could be used would be considerable.

Higher-level care.

The early experience makes it seem prudent to alert hospital ? and especially intensive healthcare services ? of potentially increased numbers of influenza patients needing hospital care/intensive care in the next few weeks, even though it is not clear as to whether this surge will materialise and at what level.

A number of the countries affected early this season have already pursued or re-emphasised these measures.

Invasive bacterial infections.

While the association between the influenza epidemics this year and the rise in two or three types of bacterial infections in not proven, clinicians could usefully be alerted to be vigilant to the possibility of the appearance of severe illness due to invasive bacteria, including invasive group A streptococcal, pneumococcal and meningococcal infections. They could also be made aware of the possibility of such bacterial co-infection in people with flu-like illness. One of the implications of this is the benefits of giving antivirals as well as anti-bacterial agents to such patients. There is some support for this from trials and observational analyses (8,9,28).

Clinical networking.

To use clinical networks for surveillance, evaluation and sharing of clinical experience (26).

Interpretation of the current situation, specific questions, remaining uncertainties, and priorities for further investigation

Q1. How likely is it that the initial experience in the first affected country (UK) will be replicated in other EU/EEA countries in terms of a) the pattern of infection and b) the impact on the health services?
The picture that emerged in the UK in December, with stress on higher-level care (1.4 prevalent cases/105 population due to influenza) when community consultation rates were low, seems unusual. It is a new development in Europe to gather hospital epidemiology on influenza patients, and so it is hard to state what is and what is not normal. However, this could be consistent with the characteristics of the A(H1N1) virus: mild disease in most, but very severe disease in a very few.

The first affected country managed to cope through some reconfiguring of services and activation of reserve plans. It should be borne in mind that it does not take very many severely ill patients to strain and disrupt higher-level services, especially when added on top of other ?winter pressures?. Also, such pressures have to be considered against the provisions of higher-level care beds and ?surge capacity?, which vary considerably across Europe (26-27). A plausible reason this season is resulting in greater stress than the pandemic 2009 is that instead of being stretched out over six months, interrupted by the school summer holidays, the period when influenza transmits intensely is now being compressed into a normal six to eight weeks in the winter when there are additional possible contributing factors of cold weather and circulation of other respiratory viruses.

The increased circulation of influenza A(H1N1)2009 and B viruses will have contributed to the excess all-cause mortality in a number of consecutive weeks: 49/2010 to 1/2011 observed in the UK (England and Wales), the Netherlands and elsewhere. However, other respiratory diseases and cold weather will also have contributed, probably more so. While no excess all-age/all-cause mortality was detected during the 2009 pandemic, waves of such excesses are quite common in other winters in Europe. What is especially uncertain this season is the extent of severe disease and mortality among older people (aged over 65 years) where diagnostic tests are less used and reporting of individual cases is weak (35).

The observation of a number of influenza cases requiring admission to an ITU is relevant and shows that preparations may be advisable to deal with the increased demand for high-level treatment during this winter?s influenza epidemics. Although the UK authorities feel what they are seeing is unusual, it will be difficult at present to entirely verify that numbers of admission are higher than what was seen during previous influenza seasons in the absence of historical data and dedicated surveillance systems for monitoring incidence of severe cases in hospital.

What can be anticipated for the rest of the season? (20 January 2011)
In the past, a rough progression of increased influenza incidence from west to east and from north to south has been observed in Europe, though the trend usually breaks down as transmission moves further east (4). This pattern of spread is occurring also in the 2010/11 season. Most of the countries are currently experiencing increased reporting of ILI/ARI but epidemics are more advanced in the western countries (see Maps 1 and 2). It should be expected that in the coming weeks increased levels of ILI/ARI consultation rates will be observed in the rest of Europe. Influenza activity will intensify in countries that have not yet reached their peaks.

However it simply cannot be determined whether countries will experience higher or lower incidence of severe cases than the UK. On the positive side, the evidence that higher levels have not happened to date would seem to be reassuring. It could be that the UK simply experienced two or three pressures coinciding (influenza, other respiratory viruses, and very cold weather) though why this should affect people in a certain age group more than others is difficult to explain. Increased ILI/ARI consultation rates usually last for four to six weeks at national level, but there are variations from year to year and between countries. It also needs to be recalled that hospital pressures usually lag behind the ILI/ARI consultation rates by one to two weeks. Equally, no country epidemics have been running this year as long as the UK?s, which began around week 47/2010, and it could be the experience is yet to come in some other countries. Also on the positive side, there are the four Nordic countries that vaccinated well and should have higher levels of protective immunity (Figure 2). On the negative side, there should be a number of countries with considerably lower numbers of immunised people than the UK (14).

Heightened need for hospital care at higher levels of dependency may be experienced in some countries. On the other hand, the levels of immunisation in the UK with seasonal vaccines are higher than in most countries. Given the predominance of influenza A(H1N1)2009 and B Victoria lineage in the current season, and given the preliminary surveillance data available, it is expected that the 2010/11 influenza season is characterised by a more similar epidemiology to that observed during the pandemic waves in 2009/10 than the previous seasonal influenza.

Whether there will be changes in the predominant viruses in European countries this season cannot be anticipated at this stage. In the southern hemisphere 2010 winter, two countries (Australia and Chile) experienced late A(H3N2) waves, while it is quite often observed that B viruses come to predominate late in some influenza seasons (16). Equally though in New Zealand the dominant viruses throughout were A(H1N1)2009. This northern hemisphere season, the predominant A virus has just changed in Japan from A(H3N2) to A(H1N1) (see NIID website). The only consistent finding is that the old pre-2009 A(H1N1) virus is entirely absent this season. Hence the importance of protecting against all three viruses in the seasonal vaccine 2010. This is relevant as there are stocks of pandemic vaccine remaining in Europe, and at least one country (the UK) had to use these due to problems in distribution and supply of seasonal vaccines (36). Since the majority of severe disease is due to A(H1N1)2009 that is certainly the most important antigen to vaccinate with if no seasonal vaccine is available. However, the evidence available suggests that seasonal vaccine 2010 would be the preferred option.

Q2. Has there been any change in the virology of the A(H1N1)2009 viruses?
To date there is no evidence of a significant change in the circulating viruses (11) (see Weekly Influenza Surveillance Overview (WISO) ? Week 3 2011). .

Q3. Has there been any emergence of antiviral resistance?
Some resistant A(H1N1) 2009 viruses have emerged almost entirely of the A(H1N1) H275Y type associated with oseltamivir resistance (37) (see also UK HPA Weekly National Influenza Report, 20 January 2011 ? Week 3). This needs careful attention to determine if there are growing numbers of transmitting resistant viruses.

Q4. What is likely to be the effectiveness of influenza vaccines and antivirals?
To date there has been no change in the virology, and the effectiveness of the current vaccine should be good. Whether it will be as high as in 2009, with a non-adjuvanted vaccine being used now, remains to be seen. The same is true for the expected effectiveness of antivirals, although the low but increasing numbers of resistant viruses will need close study.

Q5. Can changes in the viral mix be anticipated later this season?
This is a possibility that should not be dismissed. Some seasons B viruses emerge and predominate, and in two southern hemisphere countries epidemics of A(H3N2) followed waves of A(H1N1). This would support the use of trivalent seasonal vaccines over pandemic vaccine unless there is none of the former available.

Q6. Is the observation of increased incidence of two types of invasive bacterial infections in the UK of importance and likely to be related to influenza?
This is an important question but it is not one that ECDC can answer directly as it does not yet receive data on these infections. It will need to be tackled at a Member State level. It is important as early care and treatment can be crucial, and there are some data compatible with early antiviral treatment being associated with a better outcome (28).

Q7. Is an observed rise in all-cause/all-age mortality observed in a number of the Western European countries likely to be related to influenza?
Influenza will certainly have made a contribution but it may only be a minor one.

Other uncertainties

It is uncertain whether influenza attack rates in older people who were relatively spared during last season will continue to be low also during the 2010/11 season.

Though there have been anecdotal reports of severe disease due to A(H1N1)2009 in pregnant women in Europe and there are strong studies from the USA, there is a lack of analytic studies showing this in Europe. It is also important to be able to distinguish between healthy pregnant women, and pregnant women with underlying disease.

Evaluation of severity, based on indicators such as case fatality rate, case hospitalisation rate, SARI incidence, excess all-cause and P&I (pneumonia and influenza) mortality are missing, and this does not allow a proper assessment of this season?s influenza as yet.

Next update

We will review this risk assessment in two weeks? time with a view to updating. For more information, please contact: influenza@ecdc.europa.eu, where comments on this Risk Assessment are also invited.

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Department of Health, UK (England). 7 Jan 2011. Available from: (LINK)
Meijer A, Lackenby A, Hungnes O, Lina B, van der Werf S, Schweiger B, et al. Oseltamivir-resistant influenza A (H1N1) virus, Europe, 2007?08 season. Emerg Infect Dis. 2009 April. Available from: (LINK)

1 Northern Ireland, Scotland, and Wales

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**Giuseppe** · January 28, 2011, 11:06 AM

Weekly influenza surveillance overview (ECDC, January 28 2011, extract, edited)

Weekly influenza surveillance overview (ECDC, January 28 2011, extract, edited)

[Source: European Centre for Disease Prevention and Control (ECDC), full PDF document (LINK). Extract, edited.]

SURVEILLANCE REPORT

Weekly influenza surveillance overview

28 January 2011

Main surveillance developments in week 3/2011 (17 Jan 2011 ? 23 Jan 2011)

This first page contains the main developments of this week and can be printed separately or together with the more detailed information following.

During week 03/2011, 27 countries reported medium influenza activity and widespread activity was reported by 15 countries.
In addition, an increasing trend of consultations was reported by 18 countries but a decreasing trend was reported in Ireland and the UK.
Levels were high but unchanging in some other countries that were affected early; these were mostly in Belgium, France, Portugal and Spain.
However, the percentage of positive specimens from sentinel practices has decreased for the third consecutive week from 55% in week 52/2010 to 44% in week 03/2011.
The proportions of circulating influenza viruses were 68% for influenza A and 32% for influenza B.
In week 03/2011, 74 SARI cases from all causes were reported by three countries and 118 hospitalised influenza cases were reported by five countries.
Reported hospitalisations and intensive care admissions to influenza in Denmark, France, The Netherlands, and the UK have all declined in week 03/2011.
Reported hospitalisations and intensive care admissions with influenza have declined in week 3/2011 in Denmark, France, Ireland, Netherlands and the UK.
Severe cases and deaths continue to be mostly in persons in the 15?64 year age group with underlying health conditions.

Sentinel surveillance of influenza-like illness (ILI)/acute respiratory infection (ARI):

During week 03/2011, medium influenza activity was reported by 27 countries, widespread activity was reported by 15 countries and increasing trends were reported by 18 countries.

Virological surveillance:

Compared with week 52/2010, the percentage of positive sentinel specimens has decreased for three consecutive weeks from 55% to 44%. Trends for virological detections seem to have reached a plateau.

Hospital surveillance of severe acute respiratory infection (SARI):

In week 03/2011, 192 hospitalisations due to SARI from all causes and influenza infections cases were notified by eight countries.

Sentinel surveillance (ILI/ARI) - Weekly analysis ? epidemiology

During week 03/2011, 25 countries reported medium influenza activity and two countries reported high (Norway) or very high activity (Luxembourg). Only three countries, Cyprus, Sweden and the UK (Wales), reported low influenza activity.

Of the 28 countries and the UK (England and Wales) reporting geographical spread, widespread activity was reported by 15 and the UK (England), regional activity by five, local activity by five, and sporadic activity was notified by three (Slovakia, Sweden and UK Wales).

Increasing trends were reported by 18 countries and ten countries reported stable trends. Three countries?Ireland, the UK (England and Wales)?reported a decreasing trend (Table 1, Map 2).

(...)

Table 1: Epidemiological and virological overview by country, week 3/2011

[Country - Intensity - Geographic spread - Trend - No. of sentinel swabs - Dominant type - Percentage positive* - ILI per 100.000 - ARI per 100.000]

Austria - Medium - No activity - Increasing - 69 - A(H1N1)2009 - 53.6 - 6.5 - 39.2
Belgium - Medium - Widespread - Stable - 101 - A(H1N1)2009 - 72.3 - 422.4 - 1399.0
Bulgaria - Medium - Regional - Increasing - 2 - A(H1N1)2009 - 50.0 - ... - 2178.8
Cyprus - Low - Local - Stable - ... - ... - 0.0 - ...* - ...*
Czech Republic - Medium - Local - Increasing - 28 - A(H1N1)2009 - 50.0 - 76.9 - 1187.6
Denmark - Medium - Widespread - Increasing - 26 - None - 46.2 - ... - ...
Estonia - Medium - Widespread - Increasing - 102 - A(H1N1)2009 - 23.5 - 23.7 - 480.5
Finland - No information available - Widespread - Stable - 81 - A(H1N1)2009 / B - 77.8 - ... - ...
France - Medium - Widespread - Stable - 294 - A(H1N1)2009 /B - 52.0 - ... - 2619.0
Germany - Medium - Regional - Increasing - 229 - A(H1N1)2009 - 59.4 - ... - 1192.6
Greece - Medium - Regional - Increasing - 35 - A(H1N1)2009 - 74.3 - 220.8 - ...
Hungary - Medium - Widespread - Increasing - 173 - A(H1N1)2009 - 12.7 - 280.4 - ...
Iceland - Medium - Local - Stable - ... - ... - 0.0 - 18.2 - ...
Ireland - Medium - Widespread - Decreasing - 92 - A(H1N1)2009 - 35.9 - 110.4 - ...
Italy - Medium - Widespread - Increasing - 205 - A(H1N1)2009 - 36.1 - 751.9 - ...
Latvia - Medium - Widespread - Increasing - 7 - A(H1N1)2009 /B - 57.1 - 164.8 - 1382.2
Lithuania - Medium - Regional - Increasing - ... - ... - 0.0 - 137.5 - 827.2
Luxembourg - Very High - Widespread - Stable - 97 - A(H1N1)2009 / B - 61.9 - ...* - ...*
Malta - Medium - Local - Stable - ... - ... - 0.0 - ...* - ...*
Netherlands - Medium - Widespread - Increasing - 59 - A(H1N1)2009 - 71.2 - 102.9 - ...
Norway - High - Widespread - Increasing - 25 - B - 48.0 - 217.1 - ...
Poland - Medium - Regional - Increasing - 140 - A(H1N1)2009 - 31.4 - 167.2 - ...
Portugal - Medium - Widespread - Stable - 16 - A(H1N1)2009 - 56.3 - 90.7 - ...
Romania - Medium - Local - Increasing - 80 - A(H1N1)2009 - 31.3 - 23.7 - 918.6
Slovakia - Medium - Sporadic - Increasing - 1 - None - 0.0 - 156.6 - 1309.2
Slovenia - Medium - Widespread - Increasing - 69 - A(H1N1)2009 - 69.6 - 65.4 - 1954.5
Spain - Medium - Widespread - Stable - 536 - A(H1N1)2009 - 47.9 - 226.0 - ...
Sweden - Low - Sporadic - Stable - 47 - A(H1N1)2009 - 57.4 - 14.5 - ...
UK - England - Medium - Widespread - Decreasing - 341 - A / B - 18.8 - 40.7 - 410.5
UK - Northern Ireland - ... - ... - ... - ... - ... - 0.0 - ... - ...
UK - Scotland - ... - ... - ... - 99 - A(H1N1)2009 / B - 51.5 - ... - ...
UK - Wales - Low - Sporadic - Decreasing - ... - ... - 0.0 - 25.9 - ...
Europe - ... - ... - ... - 2954 - ... - 44.4 - ... - ...

*Incidence per 100 000 is not calculated for these countries as no population denominator is provided.
Note: Liechtenstein is not reporting to the European Influenza Surveillance Network

Description of the system

This surveillance is based on nationally organised sentinel networks of physicians, mostly general practitioners (GPs), covering at least 1?5% of the population in their countries. All EU/EEA Member States (except Liechtenstein) are participating. Depending on their country?s choice, each sentinel physician reports the weekly number of patients seen with influenza-like illness (ILI), acute respiratory infection (ARI) or both to a national focal point. From the national level, both numerator and denominator data are then reported to the European Surveillance System (TESSy) database. Additional semi-quantitative indicators of intensity, geographic spread and trend of influenza activity at the national level are also reported.

Virological surveillance - Weekly analysis ? virology

In week 03/2010, 23 countries and the UK (England and Scotland) reported virological data. Sentinel physicians collected 2954 specimens, of which 1311 (44.4%) were influenza positive. This percentage represents a decrease for the third consecutive week. It is noteworthy to mention that in countries with more than 100 sentinel specimens, this percentage varied from 13% to 72%. In addition, 3415 non-sentinel source specimens (i.e., specimens collected for diagnostic purpose in hospitals) were reported positive for influenza virus.

Of the 4726 influenza viruses detected during week 03/2011, 3215 (68%) were type A and 1511 (32%) were type B. In sentinel specimens, of 761 sub-typed influenza viruses, 748 (98.3%) were A(H1N1) 2009 and 13 (1.7%) were A(H3).

Since week 40/2010, of the 25 165 influenza detections in sentinel and non-sentinel specimens, 17 992 (71.5%) were influenza A and 7173 (28.5%) were influenza B viruses. Of 11 056 influenza A viruses sub-typed, 10 732 (97.1%) were A(H1N1) 2009 and 324 (2.9%) were A(H3) viruses (Table 2). Trends of virological detections since week 40/2010 are shown in Figures 1?3.

Since week 40/2010, 730 influenza viruses from sentinel and non-sentinel specimens have been characterised antigenically (Figure 4): 401 as A/California/7/2009 (H1N1)-like; 66 as A/Perth/16/2009 (H3N2)-like; 248 as B/Brisbane/60/2008-like (Victoria lineage); and 15 as B/Florida/4/2006-like (Yamagata lineage).

Since week 40/2010, Italy, Norway and the UK have reported antiviral resistance data to TESSy. A total of 684 influenza A(H1N1) 2009 and 61 influenza B viruses have been tested for susceptibility to oseltamivir, and 683 A(H1N1) 2009 viruses and 62 B viruses for susceptibility to zanamivir (Table 3). Twenty-six (3.8%) of influenza A(H1N1) 2009 viruses were resistant to oseltamivir but remained sensitive for zanamivir. All the resistant viruses carried the H275Y mutation. Seven of the 26 resistant viruses were from patients for whom no exposure to oseltamivir was reported. Data are based on single location (e.g., pyrosequencing to check for H275Y) or multiple location mutation analysis (full gene sequencing) and/or phenotypic characterisation (IC50 determination). Data should be interpreted in this context.

More details on circulating viruses can be found in the December report prepared by the Community Network of Reference Laboratories (CNRL) coordination team. Also, a detailed analysis of the viruses isolated in the UK was published in Eurosurveillance indicating no evidence of any antigenic changes in the A(H1N1) 2009 and type B viruses in that country and a good match with the seasonal vaccine viruses.

In week 03/2011, respiratory syncytial virus detections continued decreasing since their peak in week 01/2011(Figure 5).

Table 2: Weekly and cumulative influenza virus detections by type, subtype and surveillance system, weeks 40/2010?3/2011

[Virus Type / Subtype - Current Period: Sentinel - Non-Sentinel / Season: Sentinel - Non-Sentinel]

Influenza A - 890 - 2325 / 4540 - 13452
- A(H1) 2009 - 748 - 1441 / 4036 - 6696
- A (subtyping not performed) - 129 - 862 / 370 - 6566
- A (not subtypable) - 0 - 0 / 0 - 0
- A (H3) - 13 - 22 / 134 - 190
- A (H1) - 0 - 0 / 0 - 0
Influenza B - 421 - 1090 / 1839 - 5334
Total Influenza - 1311 - 3415 / 6379 - 18786

Note: A(H1)2009, A(H3) and A(H1) includes both N-subtyped and non-N-subtyped viruses

(...)

Table 3: Antiviral resistance by influenza virus type and subtype, weeks 40/2010?3/2011

[Virus type and subtype - Resistance to neuraminidase inhibitors: Oseltamivir (Isolates tested - Resistant %) / Zanamivir (Isolates tested - Resistant %) / Resistance to M2 inhibitors: Isolates tested - Resistant %]

A(H3) - ( 1 - 0 ) / ( 1 - 0 ) / ( 0 - 0 )
A(H1) - ( 0 - 0 ) / ( 0 - 0 ) / ( 0 - 0 )
A(H1)2009 - ( 684 - 26 (3.8) ) / ( 683 - 0 ) / ( 0 - 0 )
B - ( 61 - 0 ) / ( 62 - 0 ) / ( NA* - NA* )

* NA - not applicable, as M2 inhibitors do not act against influenza B viruses

(...)

Description of the system

According to the nationally defined sampling strategy, sentinel physicians take nasal or pharyngeal swabs from patients with influenza-like illness (ILI), acute respiratory infection (ARI) or both and send the specimens to influenza-specific reference laboratories for virus detection, (sub-)typing, antigenic or genetic characterisation and antiviral susceptibility testing.

(...)

Hospital surveillance ? severe acute respiratory infection (SARI) - Weekly analysis ? SARI and influenza confirmed cases

Since week 40/2010, a total of 2208 SARI cases and hospitalised influenza confirmed cases were reported to TESSy (Tables 4 and 5).

Three countries reported SARI cases from all causes; i.e., irrespective of the causative pathogen (Table 4) and five countries notified severe influenza cases admitted to hospital (Table 5).

In this latter type of reporting, only France and Ireland reported cases admitted to ICU.

In week 03/2011, 74 SARI from all causes and 118 hospitalised influenza cases were reported.

Since week 40/2010, 1470 severe influenza cases were hospitalised and 122 related fatalities were reported.

Of the 1241 influenza viruses sub-typed, 1206 (97.2%) were A(H1N1)2009, eight (0.6%) were A(H3) and 27 (2.2%) were B viruses (Table 6). Of the 573 patients admitted to ICU with available information, 427 (74.5%) needed ventilation (Table 7).

In patients for whom information was available, 40% had no prior underlying condition and obesity, morbid or not, represented the most important underlying condition (Table 7).

Table 4: Cumulative number of SARI cases from all causes, weeks 40/2010?3/2011

[Country - Number of cases - Incidence of SARI cases per 100,000 population - Number of fatal cases reported - Incidence of fatal cases per 100,000 population - Estimated population covered]

Belgium - 602 - ... - ... - ... - ...
Romania - 122 - 1.9 - 6 - 0.09 - 6413821
Slovakia - 14 - ... - ... - ... - ...
Total - 738 - ... - 6 - ... - ...

Table 5: Cumulative number of hospitalised influenza cases, weeks 40/2010?3/2011

[Country - Number of cases - Number of fatal cases reported]

Austria - 60 - 4
Spain - 777 - 54
France - 395 - 43
Ireland - 98 - 8
Portugal - 140 - 13
Total - 1470 - 122

Note: France and Ireland only reported influenza cases admitted to ICU

(...)

Table 6: Number of SARI from all causes and hospitalised influenza confirmed cases by influenza type and subtype, week 3/2011

[Virus type/subtype - Number of cases during current week - Cumulative number of cases since the start of the season]

Influenza A - 101 - 1273
- A(H1)2009 - 100 - 1206
- A(subtyping not performed) - 1 - 59
- A(H1) - ... - ...
- A(H3) - ... - 8
Influenza B - 4 - 27
Other Pathogen - ... - 33
Unknown - 87 - 875
Total - 192 - 2208

Table 7: Number of SARI cases and hospitalised influenza confirmed cases by level of care and respiratory support, weeks 40/2010?3/2011

[Respiratory support - ICU - Inpatient ward - Other - Unknown]

No respiratory support available - ... - 1 - ... - ...
No respiratory support necessary - 93 - 102 - 281 - ...
Oxygen therapy - 53 - 55 - 253 - ...
Respiratory support given unknown - 314 - 39 - 372 - 126
Ventilator - 504 - 8 - 6 - 1

(...)

Note: Other represents any other underlying condition than: asthma(ASTH), cancer(CANC), diabetes(DIAB), chronic heart disease(HEART), HIV/other immune deficiency(HIV), kidney-related conditions(KIDNEY), liver-related conditions(LIVER), chronic lung disease(LUNG), neurocognitive disorder (including seizure)(NEUROCOG), neuromuscular disorder(NEUROMUS), obesity (BMI between 30 and 40)(OBESITY), morbid obesity (BMI above 40)(OBESITYMORB), pregnancy(PREG). NONE is reported if there were no underlying conditions.

Country comments and specific information concerning hospitalised cases and mortality

This section is compiled from specific comments and published reports on the website where these are indicated by reporters. They are structured to represent influenza associated hospitalisations (and some emergency hospital consultations), use of higher level care and mortality.

Czech Republic:
- During the last week (week 3/2011), three more SARI cases with laboratory-confirmed A(H1N1)2009 were reported. All were males aged 56, 57 and 60 years and each had underlying conditions.
Denmark:
- Up to 24 January (week 3/2011), a cumulative total of 61 influenza patients have been reported by intensive care units (ICUs) in Denmark with a median age of 54 years (range 15 months to 83 years).
- Thirteen patients were admitted to an ICU in week 3/2011 compared with 19 new admissions in week 2. There is, however, still an increasing pressure on the wards, reflected by the increasing proportion of ICU beds used for influenza patients.
- On Monday 24 January 2011 at 8:00 am, 33 influenza patients were in ICUs, corresponding with 9.5% of the total number of occupied ICU beds in the country, compared with 7.5% in the week before.
- Of the ICU patients, 53 were diagnosed with influenza A, 20 of whom were reported to be further subtyped as subtype H1N1.
- Eight patients had an influenza B infection.
- Five patients with influenza A and one patient with Influenza B received extracorporal membrane oxygenation (ECMO).
- Seven patients, all with confirmed influenza A died.
- Ten patients were reported to be previously healthy people and for another 14 patients no underlying condition was reported.
- For 37 patients one or more underlying conditions were described.
- No influenza patients were reported to be pregnant.
- Initial alignment with the Danish Vaccination Registry showed that 12 of the 61 patients had received the 2010/2011 seasonal influenza vaccine between week 39 and 46 of 2010. The other 49 patients were either not vaccinated between week 39 and 46 of 2010 or had not been reported to the registry.
France:
- By week 3/2011 in the sentinel network of hospitals Oscour, 1439 emergencies consultations for influenza-like illness had been reported with 91 hospitalizations.
- The overall number of consultations and hospitalizations for influenza continued to decrease as it has been doing since week 01/2011, although the numbers in the 5 to 14 year age group have continued to increase.
- In the national network of paediatric and adult intensive care units (ICUs), the numbers have also been decreasing since week 01/2011.
- Considered cumulatively, 395 ICU influenza cases have been reported from ICUs, with influenza A (H1N1)2009 predominating (around seventy percent of cases being between 15 and 64 years of age).
- A clinical risk factor is reported in most cases; conversely, 38% of these severe cases were reported to have no identified risk factor.
- In this network there had been 43 deaths reported representing 11% of reports.
Iceland:
- There are few hospital admissions as of yet.
Ireland:
- For the 2010/2011 season to date (January 26th 2011), 749 confirmed influenza cases have been hospitalised, 98 cases have been admitted to ICU and 12 deaths have been reported to HPSC.
- At the peak this represented 1.1/105 population cases requiring higher level care
Malta:
- Situation unchanged.
The Netherlands:
- As of week 3/2011 and since October 4th 2010, 399 hospital patients were reported as infected with A(H1N1)2009 influenza virus and 20 fatalities were notified.
- The largest numbers of hospitalised admissions with influenza were patients in the 0?5 year-old agegroup.
- Underlying conditions were reported in 50% of hospitalised patients. In week 1/2011 all-cause mortality in all ages declined.
Norway:
- Total hospitalised: 82 (24 in ICU). Age 0?4, 14 hospitalised (one in ICU); age 5?14, one hospitalised (none in ICU); age 15?29, 14 hospitalised (none in ICU); age 30?64, 49 hospitalised (22 in ICU: 22); Age 65+, four hospitalised (one in ICU).
Spain:
- Information concerning severe illness due to influenza infection and admitted to hospitals comes from a surveillance system developed during the 2009/2010 pandemic season specifically for this purpose.
- From week 40/2010 to week 03/2011, 777 severe hospitalised confirmed influenza cases have been reported.
- Severely affected cases are mostly in the 15?44 and 45?64 year age groups (30% and 39%, respectively).
- Of the total, 26% were reported to be without any underlying conditions.
- Most of the severe cases and deaths have been associated with A(H1N1)2009 and are in people who have not previously been vaccinated.
UK (HPA and DH-England):
- In week 3/2011, the number of patients in England with confirmed or suspected influenza in critical care beds have declined from a peak of nearly 800 three weeks ago (equivalent to 1.4 per 105 population) to around 250 cases on January 27 2011.
- Over 80% of these are in the age group 16 to 64 years.
- Up to 19 January 2011, 338 deaths have been reported in influenza cases from across the UK.
- Ninety two per cent of the 214 cases were associated with A(H1N1)2009, 2% with untyped influenza A and 6% with influenza B infection.
- Reported deaths associated with influenza have been mainly in younger adults and children.
- Amongst cases with information on age, 3% have been younger than 5 years; 5% between 5 to 14 years; 71% from 15 to 64 years and 21% were 65 years or older.
- Of those with available information, 73% were in one of the clinical risk groups for vaccination, which includes pregnant women.
- Important reported clinical risk factors included underlying respiratory disease including asthma (27% of those in the clinical risk groups) and immunosuppression (23%).
- Of the cases with information on immunisation history, 76% had not received the 2010 trivalent vaccine and 95% had not received the pandemic vaccine.
UK (Scotland)
- An increase in influenza B is currently circulating.
- Scotland has continued to receive information on confirmed influenza cases in ITU but less than in previous weeks.
- A number of individuals with confirmed influenza have died.
- Both the ITU cases and deaths have been predominantly in individuals with influenza A(H1N1) 2009.

The report text was written by an editorial team at the European Centre for Disease Prevention and Control (ECDC): Eeva Broberg, Flaviu Plata, Phillip Zucs and Ren? Snacken. The bulletin text was reviewed by the Community Network of Reference Laboratories for Human Influenza in Europe (CNRL) coordination team: Adam Meijer, Rod Daniels, John McCauley and Maria Zambon. On behalf of the EISN members the bulletin text was reviewed by Bianca Snijders (RIVM Bilthoven, The Netherlands) and Thedi Ziegler (National Institute for Health and Welfare, Finland). Additionally the report is reviewed by experts of WHO regional office Europe

Maps and commentary used in this Weekly Influenza Surveillance Overview (WISO) do not imply any opinions whatsoever of ECDC or its partners on the legal status of the countries and territories shown or concerning their borders.

All data published in the WISO are up-to-date on the day of publication. Past this date, however, published data should not be used for longitudinal comparisons as countries tend to retrospectively update their numbers in the database.

? European Centre for Disease Prevention and Control, Stockholm, 2010

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Announcement

Archive. ECDC and EuroFlu Influenza Updates, 2011.

Archive. ECDC and EuroFlu Influenza Updates, 2011.

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