Archive. ECDC and EuroFlu Influenza Updates, 2011.

[Giuseppe]

EuroFlu - Weekly Electronic Bulletin - Week 3 : 17/01/2011-23/01/2011 - 28 January 2011, Issue N? 386 (Extract, edited)

EuroFlu - Weekly Electronic Bulletin - Week 3 : 17/01/2011-23/01/2011 - 28 January 2011, Issue N? 386 (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 3 : 17/01/2011-23/01/2011 - 28 January 2011, Issue N? 386

Continued slow increase in influenza activity across Europe

• This issue is based on data reported in week 3/2011 by 47 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 in week 3/2011.
• Pandemic influenza A(H1N1) 2009 remains the dominant virus in 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 3/2011

Of 44 countries reporting clinical data, 19 reported increasing trends in consultation rates for influenza-like illness (ILI) or acute respiratory infection (ARI).

In general, the highest consultation rates were reported for children aged 0?14 years.

Information on the intensity of influenza activity was available for 41 countries.

Most countries reported medium (29) or low (9) activity, while 1 (Luxembourg) reported very high influenza activity and 2 others (Georgia and Norway) reported high activity.

Influenza activity was reported to be widespread in 20 countries, regional in 6 countries and local in 6 countries; 11 countries reported no or sporadic activity.

Of the 23 countries reporting on the impact of influenza on health care systems, 17 described it as low and 6 as moderate.


Virological situation ? week 3/2011

Pandemic influenza A(H1N1) 2009 continued to predominate in the Region, although both influenza A and B viruses were co-dominant in 13 countries.

Influenza B was reported to be dominant in Kyrgyzstan, Norway and Ukraine.

Sentinel physicians collected 3825 respiratory specimens, of which 1674 (44%) were positive for influenza virus: 1128 (67%) were influenza A and 546 (33%) were influenza B.

Of the influenza A viruses, 976 were subtyped: 889 (91%) as pandemic A(H1) and 87 (9%) as A(H3).

In the 32 countries testing 20 or more sentinel specimens, influenza positivity ranged from 13% to 78%, with a median of 48% (mean: 45%). In addition, 4688 non-sentinel specimens were reported positive for influenza: 3247 (69%) influenza A and 1441 (31%) influenza B.

Of the influenza A viruses, 2255 were subtyped: 2201 (98%) as pandemic A(H1) and 54 (2%) as A(H3).

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

Since week 40/2010, 793 influenza viruses have been characterized antigenically: 443 were A(H1) pandemic A/California/7/2009 (H1N1)-like; 262 were B/Brisbane/60/2008-like (B/Victoria/2/87 lineage); 71 were A(H3) A/Perth/16/2009 (H3N2)-like, and 17 were B/Florida/4/2006-like (B/Yamagata/16/88 lineage).

Based on the genetic characterization of 98 influenza viruses, 69 belonged to the pandemic A/California/7/2009 A(H1N1) clade; 2 belonged to the pandemic A/Christchurch/16/2010 A(H1) clade; 5 belonged to the pandemic A/Hong Kong/2213/2010 A(H1) clade; 4 belonged to the A(H3) clade represented by A/Perth/16/2009; 8 belonged to the subgroup represented by A/Hong Kong/2121/2010 in the A/Victoria/208/2009 A(H3) clade; 2 belonged to the A(H3) clade represented by A/Victoria/208/2009; 7 belonged to the B/Bangladesh/3333/2007 clade (Yamagata lineage), and 1 to the B/Brisbane/60/2008 clade (Victoria lineage).


Cumulative virological update ? weeks 40/2010 ? 3/2011

A total of 30 113 influenza virus detections were reported during this period, of which 21 355 (71%) were influenza A and 8 758 (29%) influenza B.

Of the influenza A viruses, 13 924 were subtyped: 13 201 (95%) as pandemic influenza A(H1), 722 (5%) as influenza A(H3) and 1 (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.

Influenza activity has already peaked in 3 countries in western Europe: Ireland, Spain and the United Kingdom (England).

In week 3/2011, 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, although influenza B virus is co-dominant in 13 countries, and is the dominant virus in 3.

(...)


Network comments (where available)

• Malta
  • situation stable
• Norway
  • Total hospitalized: 82 (in ICU: 24); Age 0-4 hospitalized: 14 (in ICU: 1); Age 5-14 hospitalized: 1 (in ICU: 0); Age 15-29 hospitalized: 14 (in ICU: 0); Age 30-64 hospitalized: 49 (in ICU: 22); Age 65+ hospitalized: 4 (in ICU: 1)
• Republic of Moldova
  • One lethal case from Influenza virus A(H1N1)-2009 was registred in the 3rd week.
• Russian Federation
  • 3 letal cases from pandemic influenza A(H1N1) were registered in Russia
• Scotland
  • Increase in influenza B circulating. Continue 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.
• 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 03/2011 have been reported 777 severe hospitalised confirmed influenza cases. Severely affected cases are mostly in the 15-44 age group (30%) and in the 45-64 (39%) (26% of them without underlying conditions). 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]

EuroFlu: Three H1N1 (2009) influenza virus genetic variants isolated in European Region, Jan 28 2011

Source: EuroFlu weekly virological surveillance of influenza bulletin, full text:

THREE INFLUENZA H1N1 (2009) GENETIC VARIANTS DETECTED IN EUROPEAN REGION

(...)

Based on the genetic characterization of 98 influenza viruses:

• 69 belonged to the pandemic A/California/7/2009 A(H1N1) clade;
• 2 belonged to the pandemic A/Christchurch/16/2010 A(H1) clade;
  
• 5 belonged to the pandemic A/Hong Kong/2213/2010 A(H1) clade

(...)
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[Giuseppe]

EpiSouth Weekly Epi Bulletin ? N?149 - 19 January 2010 ? 25 January 2011 (Extract, edited): H5N1 in Egypt, Japan and South Korea; CCHF in India; AFP in Haiti.

EpiSouth Weekly Epi Bulletin ? N?149 - 19 January 2010 ? 25 January 2011 (Extract, edited)


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

EpiSouth Weekly Epi Bulletin ? N?149 - 19 January 2010 ? 25 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?149

• A(H5N1) Human influenza ? Egypt
• A(H5N1) Avian influenza ? South Korea, Japan
• ?INSIDE? Events: none
• ?OUTSIDE? events:
  • Acute Flaccid Paralysis (AFP) ? Haiti
  • Crimean Congo Hemorrhagic Fever (CCHF) ? India

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

• On 26th January 2011, the Egyptian Ministry of Health reported a new A(H5N1) human infection.
• The 122nd case is:
  • A 7 year-old child from Gharbia governorate (cf. map1)
  • The child is hospitalised, he was treated by tamiflu and is in stable condition
  • Exposure to sick/dying poultry was documented.
• In Egypt, the last human case was reported on 18th January 2011 in Alexandria Governorate (cf. eWEB n?148)
• Since the 1st case of bird flu in Egypt, the case count is 122 cases including 40 deaths.

Comments

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


Location: South Korea - Event: A(H5N1) ? Epizootic

• On 19th January 2011, the South Korean authorities reported to FAO an A(H5N1) avian influenza outbreak in 2 poultry farms located in the Gyeonggi-do province, where the capital Seoul is located (cf. map 2).
• In South Korea, the last A(H5N1) epizootics were reported on 29th December 2010 in poultries in Chungcheongnam-do and Jeolla provinces (cf. eWEB n?146).
• To date, no human avian influenza case has been reported in South Korea.

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

• On 23rd January 2011, the Japanese health authorities reported to FAO an A(H5N1) avian influenza outbreak in wild birds located in the Tohoku region, located at the North East of Honshu island (cf. map 3).
• In addition, an other highly pathogenic A(H5) avian influenza outbreak was reported in poultry farms in the Kyushu-Okonawa area, at the south of the island (the neuraminidase inhibition assays are on going).
• In Japan, the last A(H5N1) epizootic were reported on 21st December 2010 in captive wild birds (zoo) in Hokuriki region (cf. eWEB n?144).
• To date, no human avian influenza case has been reported in Japan.

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

Area: Haiti - Event: Acute Flaccid Paralysis (AFP)

• Between mid-November and end of December 2010, a cluster of 7 AFP cases including 4 deaths have been reported in Port-de-Paix, North of Haiti (cf. map 4).
• Among the 7 cases, 5 are male.
• Neurological signs appeared within 24 to 72 hours following the end of the cholera treatment. They included hypotonia followed by a bilateral ascending flaccid paralysis, reaching the respiratory muscles.
• A WHO investigation is on going in the area to determine whether the etiology is toxic (due to drugs, chemicals,?) or infectious (poliovirus or other enteroviruses,?).
• In the frame of the WHO polio eradication initiative, the formal exclusion of a polio diagnosis is necessary in front of an AFP

Comments

• In 1994, the American continent was certified Polio-free (last case in 1991).
• In 2000-2001, an outbreak caused by poliovirus type 1 vaccine strains was documented in the Dominican Republic and Haiti, with 21 confirmed cases (13 and 8 cases respectively).
• To date, according to the available information (high lethality, bilateral signs?) a polio infection seems unlikely. The situation is nonetheless followed carefully.

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

Area: India - Event: Crimean-Congo fever

• On 18th January 2011, Indian health authorities reported 5 Crimean-Congo Hemorrhagic fever (CCHF) infections in the Gujarat State (West of the country), at the border with Pakistan (cf. map 5).
• Among the 5 CCHF cases:
  • 3 died: the index case and 2 health care workers;
  • 2 others are still under treatment: the index case?s husband and additional health care worker.
• Active case finding has been set up in hospitals and at community level. Surveillance in domestic animals has been implemented too.
• To date, no additional cases have been detected.

Comments

• CCHF virus is present in many countries (cf. map 6).
• Available data showed that CCHF was circulating with particular intensity in 2008 in Turkey, Islamic Republic of Iran, several Balkan countries and Eastern Asia cf. EpiSouth CCHF thematic note. In Pakistan, cases are regularly reported.
• In 1973, in India, seroepidemiological studies found evidence of CCHF virus in humans and domestic animals in several states in the South of the country.
• The recently reported cases are the first CCHF biologically confirmed cases ever reported in India.
• The occurrence of death among health care workers prompted the CCHF biological confirmation.
• In India, there is no CCHF specific surveillance therefore this disease is probably underestimated.
• Given the proximity with Pakistan, the ecosystem similarities with neighbouring countries and the presence of the vector in India, the occurrence of confirmed CCHF sporadic cases is not an unexpected event.

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[Giuseppe]

EuroFlu - Weekly Electronic Bulletin - Week 4 : 24/01/2011-30/01/2011 - 04 February 2011, Issue N? 387 (Extract, edited): a new H1N1 2009 influenza virus genetic subgroup has been observed to emerge

EuroFlu - Weekly Electronic Bulletin - Week 4 : 24/01/2011-30/01/2011 - 04 February 2011, Issue N? 387 (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 4 : 24/01/2011-30/01/2011 - 04 February 2011, Issue N? 387

High influenza activity across Europe


This week, the EuroFlu bulletin introduces data from sentinel surveillance systems on severe acute respiratory infections (SARI). A footnote gives more information on the minimum criteria for surveillance systems reporting SARI data on the EuroFlu platform.

• This issue is based on data reported in week 4/2011 by 47 Member States in the WHO European Region.
• Influenza activity is increasing in most countries in the Region, and 23 report widespread influenza activity.
• 46% of sentinel specimens from patients with influenza-like illness (ILI) and/or acute respiratory infections (ARI), and 44% of specimens from hospitalized SARI patients were positive for influenza in week 4/2011.
• At present, 98% of antigenically characterized viruses from the 2010/2011 influenza season are similar to the viruses included in the 2010/2011 northern hemisphere influenza vaccines.

Current situation ? week 4/2011

During week 4/2011, 2 countries (Georgia and Luxembourg) reported very high intensity of influenza activity; 8 reported high intensity, and 26 reported medium intensity.

The geographical spread of influenza activity was reported to be widespread in 23 countries.

Of the 25 countries reporting on the impact of influenza on health care systems, 1 (Georgia) reported severe impact, 10 countries reported moderate impact and 14, low impact.

Clinical data also indicated increasing influenza activity in much of the WHO European Region, as 31 countries reported increasing trends in consultation rates for ILI and/or ARI.

In general, the highest consultation rates were reported for children aged 0?4 and 5?14 years.

In contrast, declining clinical trends in ILI were observed in Ireland and the United Kingdom, and some southern countries (Israel, Malta, Portugal and Spain).

Seven countries (Georgia, Kyrgyzstan, Romania, the Republic of Moldova, the Russian Federation, Serbia and Ukraine) reported clinical data on SARI from sentinel hospitals.

Hospitalizations due to SARI have increased during recent weeks in Georgia, Kyrgyzstan, Romania, the Russian Federation and Serbia, which also reported increases in clinical consultation rates for ILI or ARI.


Virological situation ? week 4/2011

Pandemic influenza A(H1N1) 2009 continued to predominate in the Region.

It was reported to be dominant in 19 countries and co-dominant with influenza B in 13 countries.

Influenza B was dominant in 4 countries.

Sentinel physicians collected 3656 respiratory specimens, of which 1691 (46%) were positive for influenza virus: 1100 (65%) were influenza A and 591 (35%) were influenza B.

Of the influenza A viruses, 981 were subtyped: 926 (94%) as pandemic A(H1) and 55 (6%) as A(H3).

In the 31 countries testing 20 or more sentinel specimens, influenza positivity ranged from 9% to 75%, with a median of 50% (mean: 45%).

In addition, 5940 non-sentinel specimens were reported positive for influenza: 4428 (75%) influenza A and 1512 (25%) influenza B.

Of the influenza A viruses, 3555 were subtyped: 3480 (98%) as pandemic A(H1) and 75 (2%) as A(H3).

Out of 195 sentinel SARI specimens collected during week 4/2011, 86 (44%) tested positive for influenza: 61 (71%) were influenza A, 25 (29%) were influenza B.

All the influenza A viruses were subtyped: 59 (97%) as pandemic A(H1), and 2 (3%) as A(H3).

The percentage of SARI specimens testing positive for influenza ranged from 10% (Ukraine) to 70% (Serbia) with a median of 45% (mean: 43%).

Respiratory syncytial viruses (RSV) continue to circulate, and were detected in 18 countries.

In 15 of these countries, however, fewer RSV detections were reported during week 4/2011 than in week 3/2011.


Cumulative virological update ? weeks 40/2010 ? 4/2011

A total of 38 300 influenza virus detections was reported during this period, of which 27 460 (72%) were influenza A and 10 840 (28%) influenza B.

Of the influenza A viruses, 18 944 were subtyped: 18 073 (95%) as pandemic influenza A(H1), 869 (5%) as influenza A(H3) and 2 as influenza A(H1).

From week 40/2010 to week 4/2011, 377 out of 1959 sentinel SARI specimens (19%) have tested positive for influenza.

Of these influenza viruses: 140 (37%) were influenza A and 237 (63%) influenza B.

Of the influenza A viruses, 127 were subtyped: 117 (92%) as pandemic influenza A(H1) and 10 (8%) as influenza A(H3).

Since week 40/2010, 1083 influenza viruses have been characterized antigenically: 618 were A(H1) pandemic A/California/7/2009 (H1N1)-like; 363 were B/Brisbane/60/2008-like (B/Victoria/2/87 lineage); 79 were A(H3) A/Perth/16/2009 (H3N2)-like; 22 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 165 influenza viruses, 90 belonged to the pandemic A/California/7/2009 A(H1N1) clade; 4 belonged to the pandemic A/Christchurch/16/2010 A(H1) clade; 23 belonged to the pandemic A/Hong Kong/2213/2010 A(H1) clade; 16 were reported as A(H1) pandemic not attributed to group category but belonging to the recently emerged A/England/142/2010 subgroup characterized by S185T substitution in the HA; 5 belonged to the A(H3) clade represented by A/Perth/16/2009; 2 belonged to the A(H3) clade represented by A/Victoria/208/2009; 17 belonged to the subgroup represented by A/Hong Kong/2121/2010 in the A/Victoria/208/2009 A(H3) clade; 7 belonged to the B/Bangladesh/3333/2007 clade (Yamagata lineage), and 1 to the B/Brisbane/60/2008 clade (Victoria lineage).

Since week 40/2010, three countries (Italy, Norway and the United Kingdom) have screened viruses for resistance to the neuraminidase inhibitors oseltamivir and zanamivir.

The United Kingdom analysed most of the viruses screened (678).

Out of the total of 714 isolates of pandemic influenza A(H1N1) 2009 viruses that were tested, 688 were sensitive to both inhibitors and 26 viruses (3.6%) carried the H275Y mutation.

These 26 viruses were resistant to oseltamivir but remained sensitive to zanamivir.

One influenza A(H3N2) virus was tested and found to be sensitive to both inhibitors.

All of the 61 influenza B viruses tested for oseltamivir resistance and the 62 tested for zanamivir resistance were found to be sensitive.

All 35 pandemic (H1N1) 2009 viruses and 2 A(H3N2) viruses that were screened for susceptibility to adamantanes were found to be resistant.


Comment

ILI and ARI consultation rates are increasing in much of the WHO European Region.

In week 4/2011, 46% of sentinel ILI/ARI specimens and 44% of sentinel SARI specimens were positive for influenza.

Influenza A(H3N2) has substantially decreased in circulation relative to pandemic influenza A(H1N1) 2009 during the course of the 2010/2011 influenza season.

Influenza B viruses continue to co-circulate.

During this week the relative distribution of influenza types and subtypes in hospitalized SARI patients appeared similar to that observed from other sentinel and non-sentinel data sources.

There is a notable difference in the proportion of influenza A to influenza B among viruses from SARI patients in week 4/2011, when compared to all viruses from SARI patients for the cumulative 2010/2011 influenza season.

This reflects the recent shift in the relative circulation of influenza A to influenza B viruses in the Caucasus, central Asia and Russian Federation, as most of the countries that are conducting sentinel SARI surveillance are located in this part of the WHO European Region.

Since the genetic characterization algorithms were put in place for pandemic influenza A(H1N1) viruses at the start of the 2010/2011 influenza season, a new genetic subgroup has been observed to emerge that is geographically dispersed and increasing in prevalence. This genetic subgroup is characterized by an S185T substitution in HA and is represented by A/England/142/2010.

To date, viruses carrying the S185T substitution remain antigenically similar to the current vaccine virus A/California/7/2009.

At present, 98% of antigenically characterized viruses from the 2010/2011 influenza season are similar to the viruses included in the 2010/2011 northern hemisphere influenza vaccines.


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)

• Czech Republic
  • Up to end of week 4/2011 a cumulative total of 34 SARI patients with laboratory-confirmed influenza A(H1N1)2009 were reported by intensive care units and 4 death.
  • Influenza activity is still increasing.
• Greece
  • In Southern Greece, dual infection of H1N1pdm with influenza B was confirmed by Real Time PCR in a non sentinel swab.
• Malta
  • situation stable
• Norway
  • Total hospitalized: 116 (in ICU: 30); Age 0-4 hospitalized: 17 (in ICU: 3); Age 5-14 hospitalized: 2 (in ICU: 1); Age 15-29 hospitalized: 17 (in ICU: 1); Age 30-64 hospitalized: 75 (in ICU: 23); Age 65+ hospitalized: 5 (in ICU: 2)
• Russian Federation
  • 3 lethal cases of pandemic influenza A(H1N1) were detected
• Serbia
  • Sentinel SARI surveillance system in SERBIA: In week 04/2011, 27 SARI from all causes were reported.
  • Out of 24 SARI specimens collected in the week 04/2011, 17(70.1%) tested positive: 16 (94.1%) were influenza A and one (5.9%) was influenza B.
  • Of the influenza A viruses, 16 were subtyped: 16(100%) as pandemic A(H1).

(...)
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[Giuseppe]

Weekly influenza surveillance overview (ECDC, February 4 2011, extract, edited)

Weekly influenza surveillance overview (ECDC, February 4 2011, extract, edited)


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

SURVEILLANCE REPORT

Weekly influenza surveillance overview

4 February 2011


Main surveillance developments in week 4/2011 (24?30 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 European countries continue to report medium to high ILI/ARI consultation rates and widespread activity. Increasing trends are mainly observed in central, eastern and southern Europe whereas countries in western Europe are reporting declining trends.
• The proportion of influenza-positive sentinel specimens has decreased for the fourth consecutive week, dropping from 54% in peak week 52/2010 to 47% in week 4/2011.
• 70% of influenza detections are type A, 30% are type B. More than 97% of subtyped influenza A viruses are A(H1N1) 2009.
• Since week 40/2010, nine countries have reported 2 488 all-cause SARI and hospitalised confirmed influenza-infected cases, including 154 fatalities. Overall, 43% of these cases were not known to have any underlying condition.
• In western countries with surveillance of severe cases, the numbers of new admissions requiring hospital care are generally dropping though numbers requiring higher level care remain substantial. Most of the severely affected cases are in the age group 15?64 years.

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

During week 04/2011, Luxembourg and Norway continued to report very high and high ILI/ARI consultation rates, respectively, while Bulgaria, Greece, Italy and Lithuania raised their intensity indicators from medium to high for the first time this season.


Virological surveillance:

In week 04/2011, sentinel physicians collected 2 768 specimens, 1 296 (46.8%) of which tested positive for influenza, representing a decrease for the fourth consecutive week. National detection rates in countries with more than 100 sentinel specimens tested ranged from 22.8% in the UK (England) to 63.5% in Luxembourg.


Hospital surveillance of severe acute respiratory infection (SARI):

In week 04/2011, 52 all-cause SARI cases and 104 hospitalised influenza-infected cases were reported. Of 1 506 cases with confirmed influenza infection since week 40/2010, 1 467 (97.4%) were type A and 39 (2.6%) were type B.


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

During week 04/2011, Luxembourg and Norway continued to report very high and high ILI/ARI consultation rates, respectively, while Bulgaria, Greece, Italy and Lithuania raised their intensity indicators from medium to high for the first time this season.

Eighteen countries and the UK (Northern Ireland and Scotland) reported medium activity whereas low activity was observed in four countries, including the UK (England) for the first time since week 48/2010 (Map 1, Table 1).

In terms of geographic spread, 18 countries in northern, western and southern Europe reported widespread activity. Four countries in central and eastern Europe reported regional activity, while eight countries reported sporadic or local activity and one country (Austria) no spread (Map 2, Table 1).

Increasing trends were reported by 16 countries in central, eastern and southern Europe, two countries less than in the preceding week. Unchanging trends were seen in eight countries in central and northern Europe. Five countries, mainly in western Europe, two more than in the preceding week, reported decreasing trends (Map 1 and 2, Table 1).

(...)


Table 1: Epidemiological and virological overview by country, week 4/2011

[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 - 66 - A(H1N1)2009 - 56.1 - 8.4 - 40.1
• Belgium - Medium - Widespread - Stable - 72 - A(H1)2009 - 68.1 - 480.2 - 1527.6
• Bulgaria - High - Widespread - Increasing - 15 - A(H1)2009 - 40.0 - ... - 2592.1
• Cyprus - Low - Sporadic - Increasing - ... - ... - 0.0 - ...* - ...*
• Czech Republic - Medium - Regional - Increasing - 29 - A(H1)2009 - 55.2 - 148.6 - 1410.8
• Denmark - Medium - Widespread - Increasing - 28 - None - 17.9 - ... - ...
• Estonia - Medium - Widespread - Increasing - 127 - A(H1N1)2009 - 47.2 - 28.6 - 600.9
• Finland - Unknown (no information available) - Widespread - Stable - 68 - A(H1N1)2009/ B - 75.0 - ... - ...
• France - Medium - Widespread - Stable - 290 - A(H1N1)2009/ B - 53.1 - ... - 2778.9
• Germany - Medium - Regional - Increasing - 251 - A(H1N1)2009 - 61.4 - ... - 1261.5
• Greece - High - Widespread - Increasing - 49 - A(H1N1)2009 - 69.4 - 436.1 - ...
• Hungary - Medium - Widespread - Increasing - 205 - A(H1)2009/B - 30.2 - 421.5 - ...
• Iceland - Medium - Local - Stable - ... - ... - 0.0 - 39.6 - ...
• Ireland - Medium - Widespread - Decreasing - 82 - B - 34.1 - 93.2 - ...
• Italy - High - Widespread - Increasing - 196 - A(H1N1)2009 - 46.9 - 1007.1 - ...
• Latvia - Low - Widespread - Increasing - 18 - A(H1)2009/B - 66.7 - 343.4 - 1493.7
• Lithuania - High - Regional - Increasing - ... - ... - 0.0 - 159.7 - 843.0
• Luxembourg - Very High - Widespread - Stable - 104 - A(H1)2009/B - 63.5 - ...* - ...*
• Malta - Medium - Local - Decreasing - ... - 0.0 - ...* - ...*
• Netherlands - Medium - Widespread - Decreasing - 33 - A(H1N1)2009 - 45.5 - 90.3 - ...
• Norway - High - Widespread - Stable - 20 - B - 60.0 - 175.1 - ...
• Poland - Medium - Regional - Increasing - 174 - A(H1)2009 - 31.0 - 192.8 - ...
• Portugal - Medium - Widespread - Stable - 10 - A(H1)2009 - 40.0 - 53.1 - ...
• Romania - Medium - Local - Increasing - 108 - A(H1N1)2009/ B - 57.4 - 34.2 - 1078.0
• Slovakia - Medium - Local - Increasing - 5 - None - 100.0 - 312.9 - 2135.3
• Slovenia - Medium - Widespread - Increasing - 59 - A(H1)2009/ B - 74.6 - 135.1 - 1840.7
• Spain - Medium - Widespread - Decreasing - 451 - A(H1N1)2009 - 39.5 - 203.3 - ...
• Sweden - Low - Widespread - Stable - 47 - A(H1)2009 - 48.9 - 35.0 - ...
• UK - England - Low - Local - Decreasing - 197 - A/B - 22.8 - 24.1 - 400.5
• UK - Northern Ireland - Medium - Local - Decreasing - 19 - B - 42.1 - 76.2 - 327.5
• UK - Scotland - Medium - Widespread - Stable - 45 - A(H1)2009/B - 44.4 - 6.6 - 260.7
• UK - Wales - ... - ... - ... - ... - ... - 0.0 - ... - ...
• Europe - ... - ... - ... - 2768 - ... - 46.8 - ... - ...

*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 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 4/2011, 26 countries reported virological data. Sentinel physicians collected 2 768 specimens, 1 296 (46.8%) of which tested positive for influenza, representing a decrease for the fourth consecutive week (Table 1, Figure 4). National detection rates in countries with more than 100 sentinel specimens tested ranged from 22.8% in the UK (England) to 63.5% in Luxembourg (Table 1). In addition, 3 468 non-sentinel source specimens (i.e. specimens collected for diagnostic purpose in hospitals) were reported positive for influenza virus.

Of the 4 764 influenza viruses detected during week 04/2011, 3 290 (69.0%) were type A and 1477 (31.0%) were type B. Of the 2 491 influenza A viruses that were subtyped, 2 468 (99.1%) were A(H1)2009 and 23 (0.9%) were A(H3) (Table 2).

Since week 40/2010, 21 588 (71.0%) of the 30 407 influenza detections in sentinel and non-sentinel specimens were influenza A and 8 819 (29.0%) were influenza B viruses. Of 13 821 influenza A viruses subtyped, 13 456 (97.4%) were A(H1)2009, 364 (2.6%) were A(H3) and one was A(H1) (Table 2). Trends of virological detections since week 40/2010 are shown in Figures 1?3.

Since week 40/2010, 1 009 influenza viruses from sentinel and non-sentinel specimens have been characterised antigenically (Figure 4): 570 (56.5%) as A/California/7/2009 (H1N1)-like; 73 (7.2%) as A/Perth/16/2009 (H3N2)-like; 346 (34.3%) as B/Brisbane /60/2008-like (Victoria lineage); and 20 (2.0%) 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 714 influenza A(H1)2009, one A(H3) virus and 61 influenza B viruses have been tested for susceptibility to oseltamivir, and 714 A(H1)2009 viruses, one A(H3) and 62 B viruses for susceptibility to zanamivir, respectively. Twenty-six (3.6%) influenza A(H1)2009 viruses were resistant to oseltamivir, but remained sensitive to zanamivir. All the resistant viruses carried the H275Y substitution. Seven of the 26 resistant viruses were from patients for whom no exposure to oseltamivir was reported.

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 significant antigenic changes in the A(H1N1)2009 and type B viruses in that country and a good match with the seasonal vaccine viruses.


Table 2: Weekly and cumulative influenza virus detections by type, subtype and surveillance system, weeks 40/2010?4/2011

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

• Influenza A - 833 - 2457 / 5420 - 16168
  • A (H1) 2009 - 718 - 1750 / 4835 - 8621
  • A (subtyping not performed) - 109 - 690 / 439 - 7328
  • A (not subtypable) - 0 - 0 / 0 - 0
  • A (H3) - 6 - 17 / 146 - 218
  • A (H1) - 0 - 0 / 0 - 1
• Influenza B - 463 - 1011 / 2347 - 6472
• Total Influenza - 1296 - 3468 / 7767 - 22640

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?4/2011

[Virus Type and subtype / Resistance to Neuraminidase inhibitors: Oseltamivir (Isolated Tested - Resistant n., %) - Zanamivir: (Isolated Tested - Resistant n. %) / Resistance to M2 inhibitors: Isolated Tested - Resistant n. %]

• A(H3N2) - ( 1 - 0 ) / ( 1 - 0 ) / ( 2 - 2 (100))
• A(H1N1) - ( 0 - 0 ) / ( 0 - 0 ) / ( 0 - 0 )
• A(H1N1) 2009 - ( 714 - 26 (3.6) ) / ( 714 - 0 ) / ( 35 - 35 (100) )
• B - ( 61 - 0 ) / ( 62 - 0 ) / ( NA? / NA* )

NA ? not applicable, as M2 inhibitors do not act against influenza B viruses.
Data are from single location (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.

(...)


Comments

Greece:

In southern Greece, dual infection with influenza A(H1N1)2009 and influenza B was confirmed by Real Time PCR in a non-sentinel swab.


CNRL coordinating team:

Since the genetic characterisation algorithms were put in place for influenza A(H1N1)2009 viruses at the start of the 2010?2011 influenza season, emergence of a new genetic subgroup has been observed that is geographically dispersed and increasing in prevalence. This genetic subgroup is characterised by a S185T substitution in HA and is represented by A/England/142/2010. To date, viruses carrying the S185T substitution remain antigenically similar to the current vaccine virus A/California/7/2009.


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

Three countries reported SARI from all causes; i.e. irrespective of the causative pathogen (Table 4), while six countries notified severe influenza cases admitted to hospital (Table 5), with France and Ireland only reporting cases admitted to intensive care (ICU).

Since week 40/2010, a total of 2 488 all-cause SARI and hospitalised confirmed influenza-infected cases, including 154 fatalities, have been reported.

In week 4/2011, 33 all-cause SARI cases and 123 hospitalised influenza cases were reported.

Of 1 506 influenza detections since week 40/2010, 1 467 (97.4%) were type A and 39 (2.6%) were type B.

Of 1 400 influenza A viruses subtyped, 1 389 (99.2%) were A(H1)2009 and 11 (0.8%) were A(H3) (Table 6).

Overall, ICU admission was reported for 1 079 patients, 559 (57.1%) of which were known to have required ventilation (Table 7). In patients for whom information was available, obesity was the most frequent underlying condition, but 43% had no prior underlying condition (Table 7).


Table 4: Cumulative number of all-cause SARI cases, weeks 40/2010?4/2011

[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 - 623 - ... - ... - ... - ...
• Romania - 149 - 2.32 - 7 - 0.11 - 6413821
• Slovakia - 20 - 0.37 - 1 - 0.02 - 5433385
• Total - 792 - ... - 8 - ... - ...

Table 5: Cumulative number of hospitalised influenza cases, weeks 40/2010?4/2011

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

• Austria - 108 - 4
• Spain - 777 - 54
• Finland - 31 - 4
• France - 470 - 54
• Ireland - 103 - 12
• Portugal - 207 - 18
• Total - 1696 - 146

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

(...)


Table 6: Number of SARI and hospitalised confirmed influenza cases by influenza virus type and subtype, week 4/2011

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

• Influenza A - 97 - 1467
• A(H1)2009 - 93 - 1389
• A(subtyping not performed) - 4 - 67
• A(H3) - ... - 11
• Influenza B - 6 - 39
• Other Pathogen - ... - 33
• Unknown - 53 - 949
• Total - 156 - 2488

Table 7: Number of SARI and hospitalised confirmed influenza cases by level of care and respiratory support, weeks 40/2010?4/2011

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

• No respiratory support available - ... - 1 - ... - ...
• No respiratory support necessary - 111 - 158 - 299 - ...
• Oxygen therapy - 56 - 65 - 256 - ...
• Respiratory support given unknown - 353 - 82 - 373 - 139
• Ventilator - 559 - 9 - 6 - 21

(...)


Note:

Other (O) 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 and UNK when the underling conditions where unknown.


Country comments and specific information concerning hospitalised cases and mortality

This section is compiled from specific comments and published reports on websites 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 (Link):
  • Up to end of week 4/2011, a cumulative total of 34 SARI patients with laboratory-confirmed influenza A(H1N1)2009 were reported by intensive care units and there were 4 deaths. Influenza activity is still increasing.
• Denmark (SSI Link):
  • Up to 24 January (week 3/2011), a cumulative total of 86 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).
  • Fifteen patients were admitted to an ICU in week 3/2011 compared with 19 new admissions in week 3.
  • There is, however, still pressure on the wards, reflected by the increasing proportion of ICU beds used for influenza patients.
  • On Monday, 31 January 2011 (8am), 35 influenza patients were in ICUs, corresponding to 10.2% of the total number of occupied ICU beds in the country, compared to 9.5% in the week before.
  • Until 24 January, of the ICU patients, 73 patients were diagnosed with Influenza A, 27 of whom were reported to be further subtyped as subtype A(H1N1)2009.
  • Thirteen patients had influenza B infection.
  • Six patients with influenza A and one patient with influenza B received extracorporal membrane oxygenation (ECMO).
  • Eleven patients with influenza A and two with influenza B died.
  • Fourteen of the 86 patients were reported to be previously healthy people and for another 22 patients no underlying condition was reported.
  • For 50 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 15 of the 86 patients had received the 2010/2011 seasonal influenza vaccine between weeks 39 and 46/2010.
  • The other 71 patients were either not vaccinated between weeks 39 and 46/2010 or had not been reported to the registry.
• France (INVS Link):
  • By week 4/2011, in the sentinel network of hospitals Oscour ,1 592 emergency consultations for influenza-like illness had been reported with 83 hospitalisations representing little change from week 3.
  • In the national network of paediatric and adult ICUs, the numbers have also been decreasing since week 01/2011.
  • Cumulatively for the season, 471 influenza cases have been reported from ICUs with influenza A(H1N1)2009 predominating and around 70% of cases being between 15 and 64 years of age.
  • A clinical risk factor is reported in most cases, conversely 37% of these severe cases were reported to have no identified risk factor.
  • In this network, there have been 54 deaths reported representing 11% of reports.
• Ireland (HPSC influenza link):
  • For the 2010/2011 season, to date (2 February 2011), 803 confirmed influenza cases have been hospitalised, 103 cases have been admitted to ICUs and 15 deaths have been reported to HPSC.
  • At the peak, this represented 1.1 cases /105 population requiring higher level (intensive) care.
  • As of 2 February, 38 (37%) of the 103 hospitalised cases remained in intensive care.
  • Seventy-four percent of the 103 cases had underlying medical conditions.
• Malta (Link):
  • Situation unchanging.
• The Netherlands (RIVM influenza link):
  • As of week 4 and since 4 October 2010, a cumulative total of 476 hospital patients were reported as infected by A(H1N1)2009 influenza virus and 25 fatalities were notified.
  • The largest numbers of hospitalised admissions with influenza were patients in the age group 0?5 years old.
  • Underlying conditions were reported in 50% of hospitalised patients.
  • In week 2, all-age all-cause mortality continued to decline.
• Spain (ISCIII Influenza link):
  • In Spain, information concerning severe illness due to influenza infection and associated admission to hospitals comes from a surveillance system developed during the 2009/2010 pandemic season specifically for this purpose.
  • Since week 40/2010 and up to week 3/2011, there have been 777 severe hospitalised confirmed influenza cases 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 were in people who have not previously been vaccinated.
• UK (HPA Influenza link and DH (England) link):
  • In week 5/2011 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 160 cases on 3 February.
  • Over 80% of these are in the age group 16 to 64 years.
  • Up to 2 February 2011, 395 deaths have been reported in influenza cases from across the UK.
  • Ninety-two percent 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 less than five years; 4% between five and 14 years; 72% 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 where vaccination is recommended, which includes pregnant women.
  • Important reported clinical risk factors were underlying respiratory disease including asthma (27% of those in the clinical risk groups) and immunosuppression (23%).
  • Of cases with information on immunisation history, 72% had not received the 2010 trivalent vaccine and 95% had not received the monovalent pandemic vaccine last season.
  • All-cause all-age deaths (due to multiple causes, not just influenza) declined in week 3/2011, although it remained above the upper limit of expected levels for this time of year.

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

-
------

[Giuseppe]

Weekly influenza surveillance overview (ECDC, Feb 11 2011, extract, edited)

Weekly influenza surveillance overview (ECDC, Feb 11 2011, extract, edited)


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

SURVEILLANCE REPORT

Weekly influenza surveillance overview

11 February 2011


Main surveillance developments in week 5/2011 (31 Jan ? 06 Feb 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 European countries continue to report medium to high influenza-like illness/acute respiratory infection consultation rates and widespread activity. Increasing trends are mainly observed in central, eastern and southern Europe whereas countries in western and northern Europe are reporting unchanging or declining trends.
• The proportion of influenza-positive sentinel specimens is gradually decreasing, having now reached 46%.
• 67% of influenza virus detections in week 5/2011 were type A, 33% were type B. In nine countries, type B detections exceeded those of type A. More than 98% of subtyped influenza A viruses were A(H1N1)2009.
• In week 5/2011, ten countries reported 194 all-cause SARI and confirmed hospitalised influenza cases, the latter mostly due to influenza A(H1N1)2009.
• Numbers of influenza infections with severe outcome have declined in western European countries (Denmark, France, the Netherlands, Ireland and the UK). However, there is now considerable uncertainty on information concerning severe cases in central and eastern European countries.

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

Luxembourg continued to report very high ILI/ARI intensity, while Hungary and Poland raised their intensity indicator from medium to high for the first time this season. With Greece, Italy, Lithuania and Norway continuing to report high consultation rates, altogether six countries observed high intensity levels.


Virological surveillance:

Sentinel physicians collected 2 644 specimens, 1 220 (46.1%) of which tested positive for influenza virus. National detection rates in countries with more than 100 sentinel specimens were below 40% in Spain and the UK (England), approximately 60% in France, Germany, Italy and Luxembourg, and below 30% in Hungary and Poland.


Hospital surveillance of severe acute respiratory infection (SARI):

Belgium, Romania and Slovakia reported 44 all-cause SARI cases including two deaths, while seven countries reported 150 hospitalised confirmed influenza-infected cases including six deaths.


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

During week 05/2011, Luxembourg continued to report very high intensity, while Hungary and Poland raised their intensity indicator from medium to high for the first time this season.

With Greece, Italy, Lithuania and Norway continuing to report high consultation rates, altogether six countries observed high intensity levels.

Seventeen countries and the UK (Scotland) reported medium intensity whereas low intensity was observed in Cyprus, Sweden and the UK (England) (Map 1, Table 1).

Twenty countries in northern, western and southern Europe reported widespread activity, including the Czech Republic, Germany and Lithuania for the first time this season.

Four countries in central and eastern Europe reported regional activity, while three countries reported sporadic or local activity and one country (Austria) no spread (Map 2, Table 1).

Increasing trends were reported by 12 countries in central, eastern and southern Europe, four countries less than in the preceding week.

Unchanging trends were seen in 12 countries in western, central and northern Europe. Four countries and the UK (Wales) reported decreasing trends (Map 1 and 2, Table 1).

(...)


Table 1: Epidemiological and virological overview by country, week 5/2011

[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 - 99 - A(H1N1)2009 - 79.8 - 7.9 - 45.9
• Belgium - Medium - Widespread - Stable - 84 - B/A(H1)2009 - 65.5 - 437.7 - 1759.9
• Bulgaria - Medium - Regional - Decreasing - 15 - B/A(H1)2009 - 53.3 - ... - 1887.2
• Cyprus - Low - Sporadic - Stable - ... - ... - 0.0 - ...* - ...*
• Czech Republic - Medium - Widespread - Increasing - 36 - A(H1N1)2009 - 72.2 - 241.5 - 1598.7
• Denmark - Medium - Widespread - Increasing - 9 - None - 11.1 - ... - ...
• Estonia - Medium - Widespread - Stable - 76 - A(H1N1)2009 - 30.3 - 26.8 - 572.4
• Finland - Unknown (no information available) - Widespread - Stable - 55 - B A(H1N1)2009 - 70.9 - ... - ...
• France - Medium - Widespread - Stable - 297 - B A(H1N1)2009 - 56.6 - ... - 3026.7
• Germany - Medium - Widespread - Increasing - 281 - A(H1N1)2009 - 59.8 - ... - 1368.4
• Greece - High - Widespread - Stable - 28 - A(H1N1)2009 - 82.1 - 366.9 - ...
• Hungary - High - Widespread - Increasing - 253 - A(H1)2009 - 7.9 - 570.0 - ...
• Iceland - Medium - Local - Stable - ... - ... - 0.0 - 42.5 - ...
• Ireland - Medium - Widespread - Stable - 63 - B - 47.6 - 86.2 - ...
• Italy - High - Widespread - Increasing - 189 - A(H1N1)2009 - 57.7 - 1102.1 - ...
• Latvia - Medium - Widespread - Increasing - 30 - B/A(H1)2009 - 50.0 - ...* - ...*
• Lithuania - High - Widespread - Increasing - ... - ... - 0.0 - 175.8 - 843.6
• Luxembourg - Very High - Widespread - Stable - 116 - B/(AH1)2009 - 60.3 - ...* - ...*
• Malta - ... - ... - ... - 0 - A(H1N1)2009 - 0.0 - ...* - ...*
• Netherlands - Medium - Widespread - Decreasing - 55 - B A(H1N1)2009 - 63.6 - 71.3 - ...
• Norway - High - Widespread - Stable - 17 - B - 82.4 - 166.5 - ...
• Poland - High - Regional - Increasing - 157 - A(H1)2009 - 28.0 - 232.0 - ...
• Portugal - Medium - Widespread - Decreasing - 16 - A(H1)2009 - 43.8 - 76.2 - ...
• Romania - Medium - Regional - Increasing - ... - ... - 0.0 - 36.8 - 1021.1
• Slovakia - Medium - Regional - Increasing - 15 - A(H1)2009 - 53.3 - 481.2 - 2689.0
• Slovenia - Medium - Widespread - Increasing - 67 - B/A(H1)2009 - 76.1 - 123.7 - 2030.2
• Spain - Medium - Widespread - Decreasing - 409 - A(H1N1)2009 - 35.2 - 178.4 - ...
• Sweden - Low - Widespread - Stable - 57 - B - 33.3 - 10.1 - ...
• UK - England - Low - Local - Stable - 151 - A/B - 21.2 - 23.6 - 429.8
• UK - Northern Ireland - ... - ... - ... - ... - ... - 0.0 - ... - ...
• UK - Scotland - Medium - Local - Stable - 69 - B A(H1N1)2009 - 46.4 - 11.1 - 309.8
• UK - Wales - Low - Sporadic - Decreasing - ... - ... - 0.0 - 13.2 - ...
• Europe - ... - ... - ... - 2644 - ... - 46.1 - ... - ...

*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


Country comments

• Luxembourg:
  • Occasional reports of bacterial secondary infections and pneumonia.
• Portugal:
  • Overall, the ILI incidence rate is decreasing, although with considerable variability.

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 5/2011, 26 countries reported virological data.

Sentinel physicians collected 2 644 specimens, 1 220 (46.1%) of which tested positive for influenza virus, showing a continuation of the slowly decreasing trend seen since week 52/2010 (Table 1, Figure 3).

National detection rates in countries with more than 100 sentinel specimens were below 40% in Spain and the UK (England), approximately 60% in France, Germany, Italy and Luxembourg, and then again below 30% in Hungary and Poland (Table 1). In addition, 3 837 non-sentinel source specimens (i.e. specimens collected for diagnostic purpose in hospitals) were reported positive for influenza virus.

Of the 5 057 influenza viruses detected during week 05/2011, 3 408 (67.4%) were type A and 1 649 (32.6%) were type B. Nine countries in western and northern Europe(1)

Since week 40/2010, 25 826 (70.6%) of the 36 601 influenza virus detections in sentinel and non-sentinel specimens were influenza A and 10 775 (29.4%) were influenza B viruses.

Of 17 328 influenza A viruses subtyped, 16 892 (97.5%) were A(H1)2009 and 436 (2.5%) were A(H3) (Table 2).

Trends of virological detections since week 40/2010 are shown in Figures 1?3. reported higher numbers of influenza B than influenza A virus detections. Of the 2 670 influenza A viruses that were subtyped, 2 627 (98.4%) were A(H1)2009 and 43 (1.6%) were A(H3) (Table 2).

Since week 40/2010, 1 297 influenza viruses from sentinel and non-sentinel specimens have been characterised antigenically (Figure 4): 737 (56.8%) as A/California/7/2009 (H1N1)-like; 80 (6.2%) as A/Perth/16/2009 (H3N2)-like; 451 (34.8%) as B/Brisbane /60/2008-like (Victoria lineage); and 29 (2.2%) as B/Florida/4/2006-like (Yamagata lineage).

Since week 40/2010, Ireland, Italy, Norway, Spain and the UK have reported antiviral resistance data to TESSy (Table 3).

Twenty-three (3.2%) of 720 influenza A(H1)2009 viruses tested for susceptibility to neuraminidase inhibitors were resistant to oseltamivir, but remained sensitive to zanamivir. All the resistant viruses carried the H275Y substitution. Nineteen resistant viruses were from patients with known exposure to antivirals. While for seven of these patients, no exposure to neuraminidase inhibitors was reported, 12 had been exposed to oseltamivir.

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 significant antigenic changes in the A(H1N1)2009 and type B viruses in that country and a good match with the seasonal vaccine viruses.


Table 2: Weekly and cumulative influenza virus detections by type, subtype and surveillance system, weeks 40/2010?5/2011

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

• Influenza A - 690 - 2718 / 6384 - 19442
  • A(H1) 2009 - 565 - 2062 / 5686 - 11206
  • A (subtyping not performed) - 111 - 627 / 527 - 7971
  • A (not subtypable) - 0 - 0 / 0 - 0
  • A (H3) - 14 - 29 / 171 - 265
  • A (H1) - 0 - 0 / 0 - 0
• Influenza B - 530 - 1119 / 3013 - 7762
• Total Influenza - 1220 - 3837 / 9397 - 27204

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

1 Belgium, Finland, Iceland, Ireland, Luxembourg, Netherlands, Norway, Sweden and United Kingdom.

(...)


Table 3: Antiviral resistance by influenza virus type and subtype, weeks 40/2010?5/2011

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

• A(H3N2) - ( 1 - 0 ) / ( 1 - 0 ) / ( 2 - 2 (100) )
• A(H1N1) - ( 0 - 0 ) / ( 0 - 0 ) / ( 0 - 0 )
• A(H1N1) 2009 - ( 720 - 23 (3.2) ) / (720 - 0 ) / ( 35 - 35 (100) )
• 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.
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

In week 5/2011, Belgium, Romania and Slovakia reported 44 all-cause SARI cases (i.e. regardless of the causative pathogen) including two deaths, while seven countries reported 150 hospitalised confirmed influenza cases including six deaths. France and Ireland only reported cases admitted to intensive care (ICU).

Since week 40/2010, ten countries have reported 3 053 all-cause SARI and hospitalised confirmed influenza cases including 224 deaths (Tables 4 and 5). The epidemic curve peaked in week 52/2010 (Figure 6).

Of 2 025 influenza virus detections since week 40/2010, 1 931 (95.4%) were type A and 61 (4.6%) were type B. Of 1 825 influenza A viruses subtyped, 1 811 (99.2%) were A(H1)2009 and 14 (0.8%) were A(H3) (Table 6).

Overall, ICU admission was reported for 1 300 patients, 665 (51.2%) of whom were known to have required ventilation (Table 7).

In patients with available information, obesity was the most frequent underlying condition, but 918 (40.9%) of 2 245 all-cause SARI and hospitalised confirmed influenza-infected cases had no prior underlying condition (Figure 7).


Table 4: Cumulative number of all-cause SARI cases, weeks 40/2010- 5/2011

[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 - 663 - ... - ... - ... - ...
• Romania - 188 - 2.93 - 12 - 0.19 - 6413821
• Slovakia - 31 - 0.57 - 3 - 0.06 - 5433385
• Total - 882 - ... - 15 - ... - ...

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

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

• Austria - 156 - 6
• Spain - 1011 - 93
• Finland - 42 - 6
• France - 532 - 63
• Ireland - 113 - 15
• Malta - 45 - 1
• Portugal - 272 - 25
• Total - 2171 - 209

(...)


Table 6: Number of SARI and hospitalised confirmed influenza cases by influenza type and subtype, week 5/2011

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

• Influenza A - 126 - 1931
  • A(H1) 2009 - 121 - 1811
  • A (subtyping not performed) - 5 - 106
  • A (H3) - ... - 14
• Influenza B - 9 - 61
• Other pathogen - ... - 33
• Unknown - 59 - 1028
• Total - 194 - 3053

Table 7: Number of SARI and hospitalised confirmed influenza cases by level of care and respiratory support, weeks 40/2010?5/2011

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

• No respiratory support available - ... - 1 - ... - ...
• No respiratory support necessary - 129 - 249 - 322 - ...
• Oxygen therapy - 65 - 91 - 265 - ...
• Respiratory support given unknown - 441 - 114 - 512 - 156
• Ventilator - 665 - 11 - 6 - 26

(...)

Note: Other (O) 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 and UNK when the underlying conditions where unknown.


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:
  • Up to the end of week 5/2011, a cumulative total of 54 SARI patients with laboratory-confirmed influenza A(H1N1)2009 virus infection have been reported by intensive care units, including six deaths.
  • Influenza activity is still increasing.
• Denmark (SSI Link):
  • Up to 7 February (week 5/2011), a cumulative total of 109 influenza patients have been reported by intensive care units (ICUs) in Denmark with a median age of 55 years (range 15 months to 83 years).
  • Fifteen patients were admitted to an ICU in week 5/2011 compared with 24 new admissions in week 4.
  • There is still pressure on the wards, reflected by the proportion of ICU beds used for influenza patients.
  • On Monday, 7 February 2011, there were 36 influenza patients in ICUs, corresponding with 10.0% of the total number of occupied ICU beds in the country, compared with 10.2% in the week before.
  • Of the ICU patients, 91 were diagnosed with influenza A, 36 of whom were reported to have been further subtyped as A(H1N1)2009.
  • Eighteen patients had an influenza B infection.
  • Eight patients with influenza A and two patients with influenza B received extracorporeal membrane oxygenation (ECMO).
  • Fifteen patients with confirmed influenza A and five with influenza B died.
  • Eighteen patients were reported to be previously healthy, and for another 29 patients, no underlying condition was reported.
  • For 62 patients, one or more underlying conditions were described.
  • One influenza patient was reported to be pregnant.
  • Initial alignment with the Danish Vaccination Registry showed that 19 of the 109 patients had received the 2010/2011 seasonal influenza vaccine between weeks 39 and 46 of 2010.
  • The other 90 patients were either not vaccinated between weeks 39 and 46 of 2010 or had not been reported to the registry.
• France (INVS Link):
  • By week 5/2011, in the sentinel network of hospitals Oscour, 1506 emergency consultations for influenza-like illness had been reported with 75 hospitalisations which is a little less than in week 4.
  • In the national network of paediatric and adult intensive care units (ICUs), the numbers have also been decreasing since week 01/2011.
  • Considered cumulatively, 534 influenza cases have been reported from ICUs with influenza A(H1N1)2009 predominating and around 70% of cases being between 15 and 64 years of age.
  • A clinical risk factor is reported in most cases.
  • Conversely, 37% of these severe cases were reported to have no identified risk factor.
  • In this network, 63 deaths have been reported which represents 12% of reports.
• Ireland (HPSC influenza link):
  • For the 2010/2011 season, to date (9 February 2011), 848 confirmed influenza cases have been hospitalised, 113 cases have been admitted to intensive care units and 18 deaths have been reported to HPSC.
  • At the peak this represented 1.1 cases /100 000 population requiring higher level (intensive) care.
  • As of 9 February, there remained 59 hospitalised cases, a total that has not changed in the last week.
  • Thirty-one of the hospitalised cases remained in intensive care.
  • Eighty-six (76%) of the 113 cases had underlying medical conditions.
  • The underlying medical conditions include: chronic respiratory disease, chronic heart disease, immunosuppression, pregnancy, metabolic disorders and morbid obesity.
  • HPSC has been informed of 18 influenza- associated deaths to date this season of which 14 had influenza A(H1N1)2009, one influenza A (unsubtyped) and three influenza B.
  • One death was in a patient in the 0?4 year age group, 13 patients were in the 15?64 year age group and four patients were aged 65 years and older.
  • Most deaths (16 out of 18) occurred in patients with underlying medical conditions.
• The Netherlands (RIVM influenza link):
  • As of week 5/2011 and since 4 October 2010, a cumulative total of 534 hospital patients were reported as infected with A(H1N1)2009 influenza virus and 32 fatalities were notified.
  • The largest numbers of hospital admissions with influenza have been children in the age group of 0?5 years.
  • Underlying conditions were reported in 54% of hospitalised patients.
  • By week 4/2011, all-age all-cause mortality was well below the statistically generated upper limit for the time of year in the Netherlands.
• Norway:
  • Total hospitalised: 141 (in ICU: 32);
    • Age 0?4 hospitalised: 28 (in ICU: 3);
    • Age 5?14 hospitalised: 2 (in ICU: 1);
    • Age 15?29 hospitalised: 19 (in ICU: 1);
    • Age 30?64 hospitalised: 83 (in ICU: 25);
    • Age 65+ hospitalised: 9 (in ICU: 2).
• Romania:
  • For week 5/2011, 15 SARI cases due to influenza A(H1N1)2009 and six SARI cases due to influenza B were reported.
  • The cumulative figures for the whole season are 32 and 14, respectively.
  • In week 5, four SARI-related deaths were reported, three of which were confirmed to be due to influenza.
• Spain (ISCIII Influenza Link):
  • In Spain, information concerning severe illness due to influenza infection with associated admission to hospitals comes from a surveillance system developed during the 2009/2010 pandemic season specifically for this purpose.
  • Since week 40/2010 and up to week 05/2011, 1011 severe hospitalised confirmed influenza cases have been reported.
  • Severely affected cases were mostly in the 15?64 year age groups (67%).
  • Conversely, 13% were less than 5 years old.
  • Of 871 cases with outcome information, 78 died, 10% with no known risk factors.
  • Of the severe cases, 632 had information available on the status of influenza vaccination for the 2010/2011 season and only 14% of 546 cases had been immunised.
  • Monovalent pandemic vaccines werereported to have been received for only 8% of hospitalised cases (38/484).
  • Eighty per cent of the cases included in the groups which were recommended influenza vaccination (chronic diseases, pregnancy, obesity, older than 60 years) had not been vaccinated this season.
• UK (HPA Influenza Link and DH (England) Link):
  • In week 6/2011, 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 100 000 population) to around 100 cases on 10 February 2010.
  • About 70% of these cases are in the age group 16 to 64 years.
  • Up to 9 February 2011, 439 deaths have been reported in influenza cases from across the UK.
  • Ninety-three per cent of the cases with additional information were associated with A(H1N1)2009, 1% with untyped influenza A and 6% with influenza B infection.
  • Reported deaths associated with influenza have been mainly among younger adults and children.
  • Amongst cases with information on age, 3% were less than 5 years old; 4% between 5 and 14 years; 72% from 15 to 64 years and 21% were 65 years or older.
  • Of those with available information, 71% were in one of the clinical risk groups for whom vaccination is recommended, which includes pregnant women.
  • Important reported clinical risk factors were underlying respiratory disease including asthma (27% of those in the clinical risk groups) and immunosuppression (23%).
  • Of cases with information on immunisation history, 72% had not received the 2010 trivalent vaccine and 95% had not received the monovalent pandemic vaccine last season.
  • All-cause all-age deaths (due to multiple causes not just influenza) declined again in week 4 and is now below the upper statistical limit of expected levels for this time of year.
• UK (Scotland):
  • The number of severely ill cases due to laboratory-confirmed influenza virus infection has fallen.
  • Similarly, the number of deaths due to influenza has fallen compared to previous weeks.

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, 2011

-
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[Giuseppe]

EuroFlu - Weekly Electronic Bulletin - Week 5 : 31/01/2011-06/02/2011 - 11 February 2011, Issue N? 388 (Extract, edited)

EuroFlu - Weekly Electronic Bulletin - Week 5 : 31/01/2011-06/02/2011 - 11 February 2011, Issue N? 388 (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 5 : 31/01/2011-06/02/2011 - 11 February 2011, Issue N? 388

Continued high influenza activity in the WHO European Region

The EuroFlu bulletin is introducing data from sentinel surveillance systems on hospitalized severe acute respiratory infections (SARI). A footnote explains the minimum criteria for inclusion of SARI data on the EuroFlu platform.

• This issue is based on data reported in week 5/2011 by 48 Member States in the WHO European Region.
• Clinical consultation rates for influenza-like illness (ILI) and/or acute respiratory infections (ARI) are increasing in 27 countries, while 9 others have passed peaks in clinical activity.
• 46% of sentinel specimens from patients with ILI and/or ARI, and 54% of specimens from sentinel SARI patients were positive for influenza in week 5/2011.
• 98% of antigenically characterized viruses from the 2010/2011 influenza season are similar to the viruses included in the 2010/2011 northern hemisphere influenza vaccines.

Current situation ? week 5/2011

During week 5/2011, 2 countries (Georgia and Luxembourg) and 3 regions of the Russian Federation reported very high intensity of influenza activity; 6 countries reported high intensity and 25 reported medium intensity.

21 countries reported widespread activity.

Of the 25 countries reporting on the impact of influenza on health care systems, 1 (Georgia) reported severe impact; 11 countries reported moderate impact and 13, low impact.

Clinical data also indicated increasing influenza activity in much of the WHO European Region, as 27 countries reported increasing trends in consultation rates for ILI and/or ARI.

Some countries in the central, south-eastern and eastern parts of the Region have reported pronounced increases in clinical ILI or ARI activity.

In general, the highest consultation rates were reported for children aged 5?14 and 0?4 years.

WHO/Europe received sentinel surveillance data on hospitalized SARI from 9 countries (Armenia, Georgia, Kazakhstan, Kyrgyzstan, Romania, the Republic of Moldova, the Russian Federation, Serbia and Ukraine).

These data indicate that, between weeks 3 and 5/2011, sentinel SARI hospitalizations in general reached their highest levels of the season to date in Georgia, Kazakhstan, Kyrgyzstan, Romania, the Russian Federation and Serbia.

Each of these countries also reported concurrent increases in clinical consultation rates for ILI or ARI.


Virological situation ? week 5/2011

Pandemic influenza A(H1N1) 2009 was reported to be dominant in 17 countries and co-dominant with influenza B in 12 countries.

Influenza B was dominant in 5 countries.

During the past few weeks, the predominance of influenza B viruses has increased in countries in western Europe, which had predominantly pandemic A(H1N1) viruses circulating at the start of their season.

In a number of eastern European countries, the earlier predominance of influenza B viruses has now shifted to a predominance of pandemic influenza A(H1N1) 2009 viruses.

Sentinel physicians collected 3125 respiratory specimens, of which 1428 (46%) were positive for influenza virus: 824 (58%) were influenza A and 604 (42%) were influenza B.

Of the influenza A viruses, 705 were subtyped: 687 (97%) as pandemic A(H1) and 18 (3%) as A(H3).

In the 26 countries testing 20 or more sentinel specimens, influenza positivity ranged from 8% to 80%, with a median of 49% (mean: 50%).

In addition, 6128 non-sentinel specimens were reported positive for influenza: 4532 (74%) influenza A and 1596 (26%) influenza B.

Of the influenza A viruses, 3792 were subtyped: 3697 (97%) as pandemic A(H1) and 95 (3%) as A(H3).

Out of 241 sentinel SARI specimens collected during week 5/2011, 129 (54%) tested positive for influenza: 94 (73%) were influenza A; 35 (27%) were influenza B.

Of the influenza A viruses, 60 were subtyped: 59 (98%) as pandemic A(H1), and 1 (2%) as A(H3).

Of the countries testing 10 or more sentinel SARI specimens, the percentage of specimens testing positive for influenza ranged from 36% (the Republic of Moldova) to 71% (Kyrgyzstan) with a median of 56% (mean: 54%).

Respiratory syncytial viruses (RSV) were detected in 16 countries; 14 of these reported fewer RSV detections during week 5/2011 than week 4/2011.


Cumulative virological update ? weeks 40/2010 ? 5/2011

A total of 46 613 influenza virus detections were reported during this period, of which 33 489 (72%) were influenza A and 13 124 (28%) were influenza B.

Of the influenza A viruses, 24 098 were subtyped: 23 072 (96%) as pandemic influenza A(H1), 1 025 (4%) as influenza A(H3) and 1 as influenza A(H1).

From week 40/2010 to week 5/2011, 566 out of 2484 sentinel SARI specimens (23%) tested positive for influenza.

Of these influenza viruses: 250 (44%) were influenza A and 316 (56%) influenza B.

Of the influenza A viruses, 183 were subtyped: 168 (92%) as pandemic influenza A(H1) and 15 (8%) as influenza A(H3).

Since week 40/2010, 1420 influenza viruses have been characterized antigenically: 834 were A(H1) pandemic A/California/7/2009 (H1N1)-like; 470 were B/Brisbane/60/2008-like (B/Victoria/2/87 lineage); 84 were A(H3) A/Perth/16/2009 (H3N2)-like; 31 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 194 influenza viruses:

• 103 belonged to the pandemic A/California/7/2009 A(H1N1) clade;
  
• 5 belonged to the pandemic A/Christchurch/16/2010 A(H1) clade;
  
• 23 belonged to the pandemic A/Hong Kong/2213/2010 A(H1) clade;
  
• 25 were reported as A(H1) pandemic not attributed to group category but belonging to the recently emerged A/England/142/2010 subgroup characterized by S185T substitution in the HA;
• 9 belonged to the A(H3) clade represented by A/Perth/16/2009;
• 1 belonged to the A(H3) clade represented by A/Brisbane/10/2007;
• 5 belonged to the A(H3) clade represented by A/Victoria/208/2009;
• 16 belonged to the subgroup represented by A/Hong Kong/2121/2010 in the A/Victoria/208/2009 A(H3) clade;
• 6 belonged to the B/Bangladesh/3333/2007 clade (Yamagata lineage), and
• 1 to the B/Brisbane/60/2008 clade (Victoria lineage).

Since week 40/2010, 5 countries (Ireland, Italy, Norway, Spain and the United Kingdom) reported screening 783 viruses for susceptibility to the neuraminidase inhibitors oseltamivir and zanamivir. 667 of these viruses were screened by the United Kingdom.

Of 720 isolates of pandemic influenza A(H1N1) 2009 viruses that were tested, 697 were sensitive to both inhibitors and 23 viruses (3.2%) were resistant to oseltamivir, as determined by the presence of the H275Y mutation.

These 23 remained sensitive to zanamivir.

1 influenza A(H3N2) virus was tested and found to be sensitive to both inhibitors.

All of the 61 influenza B viruses tested for susceptibility to oseltamivir and the 62 tested for susceptibility to zanamivir were found to be sensitive.

All 35 pandemic influenza A(H1N1) 2009 viruses and 2 A(H3N2) viruses that were screened for susceptibility to adamantanes were found to be resistant.


Comment

ILI and ARI consultation rates continue to increase in the WHO European Region, particularly in the central, eastern and south-eastern parts, and the percentage of sentinel specimens positive for influenza remains high. Influenza activity is progressing in a west-to-east manner across the Region, with pandemic influenza A(H1N1) 2009 circulation generally decreasing in the western part of the Region and increasing in the eastern.

Influenza B is becoming relatively more predominant in countries where the prevalence of pandemic influenza A (H1N1) 2009 is decreasing.

This shift, with relatively more A(H1N1) 2009 viruses circulating in the eastern part of the Region, may explain the notable difference in the proportion of influenza A to influenza B viruses among SARI patients in week 5/2011, when compared to all SARI viruses for the cumulative 2010/2011 influenza season.

This is because most of the countries conducting sentinel SARI surveillance are in the central and eastern part of the WHO European Region.

98% of antigenically characterized viruses from the 2010/2011 influenza season are similar to the viruses recommended for inclusion in the 2010/2011 northern hemisphere influenza vaccines.


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)

• Czech Republic
  • Up to end of week 5/2011 a cumulative total of 54 SARI patients with laboratory-confirmed influenza A(H1N1)2009 have been reported by intensive care units and there were 6 death.
  • Influenza activity is still increasing.
• Lithuania
  • Lithuania have few cases of double infection of A H1pdm and influenza B detected by Real Time PCR in a non sentinel swabs.
• Luxembourg
  • Occasional reports of bacterial secondary infections and pneumonia
• Norway
  • Total hospitalized: 141 (in ICU: 32);
    • Age 0-4 hospitalized: 28 (in ICU: 3);
    • Age 5-14 hospitalized: 2 (in ICU: 1);
    • Age 15-29 hospitalized: 19 (in ICU: 1);
    • Age 30-64 hospitalized: 83 (in ICU: 25);
    • Age 65+ hospitalized: 9 (in ICU: 2)
• Portugal
  • Overall the ILI incidence rate is decreasing although with considerable variability.
• Scotland
  • The number of severely ill cases due to influenza (laboratory confirmed) has fallen.
  • Similarly the number of deaths due to influenza has fallen compared to previous weeks
• Serbia
  • Sentinel SARI surveillance system in SERBIA: In week 05/2011, 42 SARI from all causes were reported.
  • Out of 34 SARI specimens collected in the week 05/2011, 20 (58,8%) tested positive: 19 (95%) were influenza A and one (5%) influenza B.
  • Of the influenza A viruses 16 (84,2%) were subtyped as pandemic A(H1) and 3 (15,8%) as A(H3).
• 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 05/2011 1011 severe hospitalised confirmed influenza cases have been reported (all with age information): 13% have been less than 5 years..

(...)
-
------

[Giuseppe]

EuroFlu - Weekly Electronic Bulletin - Week 6 : 07/02/2011-13/02/2011 - 18 February 2011, Issue N? 389 (Extract, edited)

EuroFlu - Weekly Electronic Bulletin - Week 6 : 07/02/2011-13/02/2011 - 18 February 2011, Issue N? 389 (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 6 : 07/02/2011-13/02/2011 - 18 February 2011, Issue N? 389

High influenza activity in the WHO European Region

• This issue is based on data reported in week 6/2011 by 45 Member States in the WHO European Region.
• Clinical activity has apparently moved past peak in 24 countries of the Region.
• 44% of sentinel specimens from patients with influenza-like illness (ILI) and/or acute respiratory infections (ARI), and 39% of specimens from sentinel severe acute respiratory infection (SARI) patients were positive for influenza.
• 97% of antigenically characterized viruses from the 2010/2011 influenza season are similar to the viruses included in the 2010/2011 northern hemisphere influenza vaccines.

Current situation ? week 6/2011

During week 6/2011, 2 countries (Georgia and Luxembourg) and the Siberian region of the Russian Federation reported very high intensity of influenza activity; 8 countries reported high intensity; 28 reported medium intensity and 11 countries, low intensity.

23 countries reported widespread activity.

Of the 26 countries reporting on the impact of influenza on health care systems, 1 (Georgia) reported severe impact; 14 countries reported moderate impact and 11, low impact.

Of the 41 countries reporting on consultation rates for ILI and ARI, 8 (Albania, Belarus, the Czech Republic, Iceland, Kazakhstan, the Republic of Moldova, Serbia and Slovakia) reported increases while 6 (Ireland, Israel, Malta, Norway, Spain and the United Kingdom (England)) reported decreases.

Influenza activity has apparently passed its peak in 24 countries in the Region.

In general, the highest consultation rates were reported for children aged 0?4 and 5?14 years.

WHO/Europe received sentinel surveillance data on hospitalized SARI cases from 9 countries (Armenia, Georgia, Kazakhstan, Kyrgyzstan, Romania, the Republic of Moldova, the Russian Federation, Serbia and Ukraine).

Sentinel SARI hospitalizations are at the highest levels observed for the season so far in Georgia and Serbia.

In Georgia, however, outpatient clinical consultation rates declined from week 5 to week 6, while the relative percentage of both SARI and ILI specimens testing positive for influenza B increased.

Sentinel SARI hospitalizations in Kazakhstan, Kyrgyzstan, Romania and the Russian Federation have declined somewhat from observed peaks in weeks 3?5, but remain notably elevated above pre-season levels, with 30?50% of sentinel SARI specimens testing positive for influenza in each of these countries.

Sentinel SARI admissions in the Republic of Moldova and Ukraine are at levels below prior peaks. Nevertheless, a significant percentage of sentinel SARI specimens continue to test positive for influenza, and the proportion of influenza A detections in sentinel SARI specimens in Ukraine increased in week 6.

Further information on the sentinel SARI surveillance systems represented in the EuroFlu bulletin can be found in the ?Overview of sentinel SARI systems in EuroFlu?.


Virological situation ? week 6/2011

Pandemic influenza A(H1N1) 2009 was reported to be dominant in 14 countries and co-dominant with influenza B in 12 countries.

Influenza B was dominant in 7 countries.

During the past few weeks, the predominance of influenza B viruses has increased in countries in western Europe, which had predominantly pandemic A(H1N1) viruses circulating at the start of their season.

In a number of eastern European countries, the predominance has now shifted from influenza B viruses to pandemic influenza A(H1N1) 2009 viruses.

Sentinel physicians collected 3109 respiratory specimens, of which 1373 (44%) were positive for influenza virus: 712 (52%) were influenza A and 661 (48%) were influenza B.

Of the influenza A viruses, 647 were subtyped: 606 (94%) as pandemic A(H1) and 41 (6%) as A(H3).

In the 31 countries testing 20 or more sentinel specimens, influenza positivity ranged from 9% to 91%, with a median of 46% (mean: 48%).

In addition, 6739 non-sentinel specimens were reported positive for influenza: 5050 (75%) influenza A and 1689 (25%) influenza B.

Of the influenza A viruses, 4526 were subtyped: 4445 (98%) as pandemic A(H1) and 81 (2%) as A(H3).

Out of 320 sentinel SARI specimens collected during week 6/2011, 125 (39%) tested positive for influenza: 81 (65%) were influenza A; 44 (35%) were influenza B.

Of the influenza A viruses, 59 were subtyped: 58 (98%) as pandemic A(H1), and 1 (2%) as A(H3).

Of the 7 countries testing 10 or more sentinel SARI specimens, the percentage of specimens testing positive for influenza ranged from 29% (Kazakhstan) to 55% (Republic of Moldova) with a median of 44% (mean: 43%).

Respiratory syncytial viruses (RSV) were detected in 16 countries; 14 of these reported fewer detections in week 6/2011 than during previously observed peaks of RSV activity.


Cumulative virological update ? weeks 40/2010 ? 6/2011

A total of 55 529 influenza virus detections were reported during this period, of which 39 778 (72%) were influenza A and 15 751 (28%) were influenza B.

Of the influenza A viruses, 29 727 were subtyped: 28 492 (96%) as pandemic influenza A(H1), 1 234 (4%) as influenza A(H3) and 1 as influenza A(H1).

From week 40/2010 to week 6/2011, 756 out of 3058 sentinel SARI specimens (25%) tested positive for influenza.

Of these influenza viruses, 345 (46%) were influenza A and 411 (54%) influenza B.

Of the influenza A viruses, 246 were subtyped: 230 (93%) as pandemic influenza A(H1) and 16 (7%) as influenza A(H3).

Since week 40/2010, 1818 influenza viruses have been characterized antigenically: 1043 were A(H1) pandemic A/California/7/2009 (H1N1)-like; 626 were B/Brisbane/60/2008-like (B/Victoria/2/87 lineage); 93 were A(H3) A/Perth/16/2009 (H3N2)-like; 55 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 311 influenza viruses:

• 147 belonged to the pandemic A/California/7/2009 A(H1N1) clade;
• 7 belonged to the pandemic A/Christchurch/16/2010 A(H1) clade;
• 23 belonged to the pandemic A/Hong Kong/2213/2010 A(H1) clade;
• 25 were reported as A(H1) pandemic not attributed to group category but belonging to the recently emerged A/England/142/2010 subgroup characterized by S185T substitution in the HA;
• 9 belonged to the A(H3) clade represented by A/Perth/16/2009;
• 6 belonged to the A(H3) clade represented by A/Victoria/208/2009;
• 20 belonged to the subgroup represented by A/Hong Kong/2121/2010 in the A/Victoria/208/2009 A(H3) clade;
• 8 belonged to the B/Bangladesh/3333/2007 clade (Yamagata lineage), and
• 66 to the B/Brisbane/60/2008 clade (Victoria lineage).

Since week 40/2010, 5 countries (Ireland, Italy, Norway, Spain and the United Kingdom) have screened 801 viruses for susceptibility to the neuraminidase inhibitors oseltamivir and zanamivir.

The United Kingdom analysed most of the viruses screened (671).

Out of the total of 738 isolates of pandemic influenza A(H1N1) 2009 viruses that were tested, 710 were sensitive to both inhibitors and 28 viruses (3.8%) carried the NA H275Y mutation.

These 28 viruses were resistant to oseltamivir but remained sensitive to zanamivir.

1 influenza A(H3N2) virus was tested and found to be sensitive to both inhibitors.

All of the 61 influenza B viruses tested for susceptibility to oseltamivir and the 62 tested for susceptibility to zanamivir were found to be sensitive.

All 35 pandemic influenza A(H1N1) 2009 viruses and 2 A(H3N2) viruses that were screened for susceptibility to adamantanes were found to be resistant.


Comment

ILI and ARI clinical consultation rates and the percentage of sentinel specimens testing positive for influenza remain high in the WHO European Region, particularly in the central, eastern and south-eastern parts. Influenza activity is generally progressing in a west-to-east manner across the Region, with pandemic influenza A(H1N1) 2009 circulation decreasing in the western part and increasing in the central and eastern parts.

Influenza B is becoming relatively more predominant in countries where the circulation of pandemic influenza A (H1N1) 2009 is decreasing.

This pattern is also apparent in sentinel SARI hospitalizations, which are associated with both influenza A and influenza B infections.

Currently 97% of antigenically characterized viruses from the 2010/2011 influenza season are similar to the viruses recommended for inclusion in the 2010/2011 northern hemisphere influenza vaccines.


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.


Footnote: reporting of SARI data

The EuroFlu bulletin presents data from countries that have established sentinel SARI surveillance systems that meet the following two criteria:

• hospitalized patients meeting a syndromic SARI case definition are routinely tracked, tested for influenza, and reported to the national level on a weekly basis from a standard and generally stable number of sentinel hospitals; and
• there has been consistent weekly reporting of epidemiological and virological data from the sentinel SARI system to the EuroFlu surveillance platform during the 2010/2011 influenza season.

Further information on severe cases associated with influenza virus infections in the European Region can be found in the ECDC Weekly Influenza Surveillance Overview.


Erratum:

For the genetic characterizations, 66 viruses in total were characterized as B/Brisbane/60/2008 clade (Victoria lineage). The antigenic graph for Europe presents a total of 4 and is not correct.

(...)


Network comments (where available)

• Czech Republic
  • Influenza activity is still increasing.
  • Up to end of week 6/2011 a cumulative total of 96 SARI patients with laboratory-confirmed influenza A(H1N1)2009 have been reported by intensive care units and there were 12 death.
• Greece
  • In a single clinical specimen a coinfection of influenza B virus and A(H1N1)2009 virus was confirmed by real time PCR.
  • A total of 60 clinical specimens positive for A(H1N1)2009 (including deaths and SARI cases) were examined by Real Time PCR for the presence of tamiflu resistance mutation H275Y.
  • None of these isolates were confirmed to carry the mutation.
• Malta
  • situation stable
• Norway
  • Total hospitalized: 141 (in ICU: 32);
    • Age 0-4 hospitalized: 28 (in ICU: 3);
    • Age 5-14 hospitalized: 2 (in ICU: 1);
    • Age 15-29 hospitalized: 19 (in ICU: 1);
    • Age 30-64 hospitalized: 83 (in ICU: 25);
    • Age 65+ hospitalized: 9 (in ICU: 2)
• Republic of Moldova
  • Two lethal cases from influenza A(H1N1)2009 were registred in the 6th week.
• Serbia
  • Sentinel SARI surveillance system in SERBIA: In week 06/2011, 43 SARI from all causes were reported.
  • Out of 40 SARI specimens collected in the week 06/2011, 27 (67,5%) tested positive: 26 (96,3%) were influenza A and one (3,7%) influenza B.
  • Of the influenza A viruses 23 (88,5%) were subtyped as pandemic A(H1) and 3 (11,5%) as A(H3).
• Slovenia
  • In the week 6 for the first time in this season in Slovenia influenza B (Vic) virus prevails over A (H1)2009 in both, sentinel samples and samples from other sources.
• Spain
  • In Spain information concerning severe illness due to influenza infection with associated admission to hospitals comes from a surveillance system developed during the 2009/2010 pandemic season specifically for this purpose.
  • Since week 40/2010 and up to week 06/2011 1059 severe hospitalised confirmed influenza cases have been reported.
  • Severely affected cases were mostly in the 15-64 year age groups (66%).
  • Conversely 13% were less than five years old.
  • Of 944 cases with outcome information 106 died (13% with no known risk factors).
  • Of the severe cases 662 had information available on the status of influenza vaccination for the 2010/2011 season and only 89 (13%) cases had been immunised.
  • Monovalent pandemic vaccines 2009 were reported to have been received for only 8% of hospitalised cases (41/504).
  • Eighty per cent of the cases included in the groups which were recommended influenza vaccination (chronic diseases / pregnancy / obesity / older than 60 years) had not been vaccinated this season

(...)
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[Giuseppe]

Weekly influenza surveillance overview (ECDC, Feb 18 2011, extract, edited)

Weekly influenza surveillance overview (ECDC, Feb 18 2011, extract, edited)


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

SURVEILLANCE REPORT

Weekly influenza surveillance overview

18 February 2011


Main surveillance developments in week 6/2011 (07 Feb 2011 ? 13 Feb 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 European countries continue to report medium to high influenza-like illness /acute respiratory infection consultation rates and widespread activity. Decreasing ILI/ARI trends were reported by 14 countries.
• The proportion of influenza virus-positive sentinel specimens has gradually decreased to 43% after peaking in week 52/2010 at 57%
• Sixty-seven per cent of influenza virus detections in week 6/2011 were type A, 33% were type B. More than 99% of subtyped influenza A viruses were A(H1N1)2009.
• In week 6/2011, ten countries reported 180 all-cause SARI and hospitalised confirmed influenza cases, the latter mostly due to influenza virus A(H1N1)2009 infection.
• Numbers of influenza infections with severe outcome have decreased in western European Union countries (Denmark, France, the Netherlands, Ireland, Spain and the UK). However, there is considerable uncertainty about severe cases in a number of countries, especially those in central, eastern and south-eastern European countries, because of limited hospital surveillance.

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

During week 06/2011, four countries (Greece, Hungary, Italy and Sweden) observed high intensity levels of ILI/ARI and Luxembourg continued to report very high intensity. Fourteen countries reported decreasing trends.


Virological surveillance:

Sentinel physicians collected 2 351 specimens, 1 022 (43.5%) of which tested positive for influenza virus.


Hospital surveillance of severe acute respiratory infection (SARI):

Belgium, Romania and Slovakia reported 75 all-cause SARI cases including three deaths, while seven countries reported 105 hospitalised confirmed influenza-infected cases including one death.


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

During week 06/2011, four countries (Greece, Hungary, Italy and Sweden) observed high intensity levels of ILI/ARI and Luxembourg continued to report very high intensity. Nineteen countries and the UK (Scotland) reported medium intensity while low intensity was reported by Cyprus, Malta and the UK (England, Northern Ireland and Wales) (Map 1, Table 1).

Eighteen countries across Europe reported widespread activity while the activity decreased from widespread to regional in Germany and from local to sporadic in the UK (England). In Iceland, the activity increased to regional for the first time this season.

Overall, six countries in northern, central and eastern Europe reported regional activity, while three countries reported sporadic or local activity and one country (Austria) no spread (Map 2, Table 1).

Increasing trends were reported by only four countries (Austria, Czech Republic, Iceland and Slovakia), eight countries less than in the preceding week. Unchanging trends were seen in 10 countries. Fourteen countries, ten more than in week 05/2011, reported decreasing trends (Map 1 and 2, Table 1).

(...)


Table 1: Epidemiological and virological overview by country, week 6/2011

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

• Austria - Medium - No activity - Increasing - 70 - A(H1N1)2009 - 68.6 - ... - 33.2
• Belgium - Medium - Widespread - Stable - 53 - B A(H1)2009 - 62.3 - 391.1 - 1695.1
• Bulgaria - Medium - Regional - Decreasing - 14 - A(H1)2009 - 28.6 - ... - 1439.3
• Cyprus - Low - Sporadic - Stable - ... - ... - 0.0 - ...* - ...*
• Czech Republic - Medium - Widespread - Increasing - 29 - B A(H1N1)2009 - 75.9 - 296.7 - 1583.2
• Denmark - Medium - Widespread - Decreasing - 51 - None - 25.5 - ... - ...
• Estonia - Medium - Widespread - Decreasing - 55 - A(H1N1)2009 - 34.5 - 23.0 - 502.3
• Finland - Unknown (no information available) - Widespread - Stable - 62 - B A(H1)2009 - 71.0 - ... - ...
• France - Medium - Widespread - Stable - 232 - B A(H1N1)2009 - 41.4 - ... - 2824.4
• Germany - Medium - Regional - Stable - 305 - A(H1N1)2009 - 61.0 - ... - 1342.3
• Greece - High - Widespread - Decreasing - 38 - A(H1N1)2009 - 76.3 - 361.0 - ...
• Hungary - High - Widespread - Stable - 162 - A(H1)2009 - 9.3 - 587.8 - ...
• Iceland - Medium - Regional - Increasing - ... - ... - 0.0 - 57.5 - ...
• Ireland - Medium - Widespread - Decreasing - 53 - B - 39.6 - 50.3 - ...
• Italy - High - Widespread - Decreasing - 230 - A(H1N1)2009 - 36.5 - 965.4 - ...
• Latvia - Medium - Widespread - Decreasing - 21 - B A(H1)2009 - 47.6 - ...* - ...*
• Lithuania - ... - ... - ... - ... - ... - 0.0 - ... - ...
• Luxembourg - Very High - Widespread - Stable - 108 - B A(H1)2009 - 62.0 - ...* - ...*
• Malta - Low - Local - Decreasing - ... - ... - 0.0 - ...* - ...*
• Netherlands - Medium - Widespread - Decreasing - 31 - B - 29.0 - 70.9 - ...
• Norway - Medium - Widespread - Decreasing - 25 - B - 60.0 - 145.8 - ...
• Poland - Medium - Regional - Decreasing - 114 - A(H1)2009 - 29.8 - 180.8 - ...
• Portugal - Medium - Widespread - Decreasing - 8 - A(H1)2009 - 50.0 - 49.9 - ...
• Romania - Medium - Widespread - Stable - 55 - B A(H1N1)2009 - 45.5 - 33.3 - 1012.6
• Slovakia - Medium - Regional - Increasing - 16 - None - 75.0 - 572.4 - 2820.6
• Slovenia - Medium - Widespread - Stable - 39 - B A(H1)2009 - 82.1 - 69.6 - 1711.9
• Spain - Medium - Regional - Decreasing - 340 - B - 36.5 - 152.3 - ...
• Sweden - High - Widespread - Stable - 55 - B - 72.7 - 12.6 - ...
• UK - England - Low - Sporadic - Decreasing - 137 - B - 11.7 - 18.4 - 424.7
• UK - Northern Ireland - Low - Local - Decreasing - ... - ... - 0.0 - 35.6 - 372.6
• UK - Scotland - Medium - Local - Decreasing - 48 - B - 41.7 - 8.9 - 262.1
• UK - Wales - Low - Sporadic - Decreasing - ... - ... - 0.0 - 8.3 - ...
• Europe - ... - ... - ... - 2351 - ... - 43.5 - ... - ...

*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 6/2011, 25 countries and the UK (England and Scotland) reported virological data.

Sentinel physicians collected 2 351 specimens, 1 022 (43.5%) of which tested positive for influenza virus, continuing the slowly decreasing trend seen since week 52/2010 (Table 1, Figure 3).

National detection rates increased in some countries, e.g. Denmark, Hungary, Slovakia, Slovenia and Sweden, but decreased in many countries in western, southern and central Europe (Table 1). In addition, 3 958 non-sentinel source specimens (i.e. specimens collected for diagnostic purposes in hospitals) were reported positive for influenza virus (Table 2).

Of the 4 980 influenza viruses detected during week 06/2011, 3 338 (67.0%) were type A and 1 642 (33.0%) were type B.

Five countries in western and northern Europe reported influenza B as the dominant type (Table 1).

Of the 2 826 influenza A viruses that were subtyped, 2 802 (99.2%) were A(H1)2009 and 24 (0.8%) were A(H3) (Table 2).

Since week 40/2010, 29 520 (69.9%) of the 42 261 influenza virus detections in sentinel and non-sentinel specimens were influenza A and 12 741 (30.1%) were influenza B viruses. Of 20 473 influenza A viruses subtyped, 19 992 (97.7%) were A(H1)2009 and 481 (2.3%) were A(H3) (Table 2). Trends of virological detections since week 40/2010 are shown in Figures 1?3.

Since week 40/2010, 1 655 influenza viruses from sentinel and non-sentinel specimens have been characterised antigenically (Figure 4): 915 (55.3%) as A/California/7/2009 (H1N1)-like; 86 (5.2%) as A/Perth/16/2009 (H3N2)-like; 601 (36.3%) as B/Brisbane /60/2008-like (Victoria lineage); and 53 (3.2%) as B/Florida/4/2006-like (Yamagata lineage).

Since week 40/2010, Ireland, Italy, Norway, Spain and the UK have reported antiviral resistance data to TESSy. A summary is shown in Table 3. Twenty-eight of 738 (3.8%) influenza A(H1)2009 viruses tested for susceptibility to neuraminidase inhibitors were resistant to oseltamivir, but remained sensitive to zanamivir. All the resistant viruses carried the neuraminidase H275Y substitution. Eight of 24 resistant viruses, from patients for which exposure to antivirals was known, were from patients that had not been treated with oseltamivir.

More details on circulating viruses can be found in the December report prepared by the Community Network of Reference Laboratories (CNRL) coordination team. The viruses circulating this season remain well-matched with the 2010/11 seasonal vaccine viruses.


Table 2: Weekly and cumulative influenza virus detections by type, subtype and surveillance system, weeks 40/2010?6/2011

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

• Influenza A - 514 - 2824 / 7044 - 22476
  • A(H1) 2009 - 450 - 2352 / 6286 - 13706
  • A (subtyping not performed) - 59 - 453 / 571 - 8476
  • A (not subtypable) - 0 - 0 / 0 - 0
  • A (H3) - 5 - 19 / 187 - 294
  • A (H1) - 0 - 0 / 0 - 0
• Influenza B - 508 - 1134 / 3664 - 9077
• Total Influenza - 1022 - 3958 / 10708 - 31553

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?6/2011

[Virus Type / Subtype - Resistance to neuraminidase inhibitors: Oseltamivir (Isolated Tested - Resistant n (%) / Zanamivir: (Isolated tested / Resistant n (%) / Resistance to M2 inhibitors: (Isolated Tested / Resistant n (%))]

• A(H3N2) - ( 1 - 0 ) / ( 1 - 0 ) / ( 2 - 2 (100) )
• A(H1N1) - ( 0 - 0 ) / ( 0 - 0 ) / ( 0 - 0 )
• A(H1N1) 2009 - ( 738 - 28 (3.8) ) / ( 738 - 0 ) / ( 35 - 35 (100) )
• B - ( 61 - 0 ) / ( 62 - 0 ) / ( NA* / NA* )

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

(...)


Country comments

• Greece:
  • In a single clinical specimen a co-infection of influenza B virus and A(H1N1)2009 virus was confirmed by real time PCR.
  • A total of 60 clinical specimens positive for A(H1N1)2009 (including deaths and SARI cases) were examined by real-time PCR for the presence of Tamiflu resistance mutation H275Y.
  • None of these isolates were shown to carry the mutation.
• Slovenia:
  • In week 6, for the first time this season, in Slovenia influenza B (Vic) virus prevails over A(H1)2009 in both sentinel samples and samples from other sources.

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, three countries have reported SARI cases from all causes; i.e., irrespective of the causative pathogen (Table 4), and seven countries notified severe influenza cases admitted to hospital (Table 5). In this latter type of reporting, France and Ireland reported only cases admitted to intensive care (ICU).

In week 6/2011, Belgium, Romania and Slovakia reported 75 all-cause SARI cases including three deaths, while seven countries reported 105 hospitalised confirmed cases of influenza virus infection including one death.

Since week 40/2010, ten countries have reported 3 352 all-cause SARI and hospitalised confirmed cases of influenza virus infection including 252 deaths (Tables 4 and 5). The epidemic curve peaked in week 52/2010 (Figure 6).

Of 2 214 influenza virus detections since week 40/2010, 2 139 (96.6%) were type A and 75 (3.4%) were type B. Of 2 026 influenza A viruses subtyped, 2 012 (99.3%) were A(H1)2009 and 14 (0.7%) were A(H3) (Table 6). The percentage of influenza B virus detections is ten times higher (weeks 40/2010?6/2011, 34.2%) in the outpatient sentinel samples (Table 2) than it is for the SARI or for the severe influenza cases admitted to hospital.

Overall, ICU admission was reported for 1 357 patients, 705 (52.0%) of whom were known to have required ventilation (Table 7). In patients for whom information was available, obesity was the most frequent underlying condition, but 1 022 (42.0%) of 2 436 all-cause SARI and hospitalised confirmed influenza-infected cases had no known prior underlying condition (Figure 7).


Table 4: Cumulative number of all-cause SARI cases, weeks 40/2010- 6/2011

[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 - 720 - ... - ... - ... - ...
• Romania - 217 - 3.38 - 14 - 0.22 - 6413821
• Slovakia - 42 - 0.77 - 4 - 0.07 - 5433385
• Total - 979 - ... - 18 - ... - ...

Table 5: Cumulative number of hospitalised influenza cases, weeks 40/2010?6/2011

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

• Austria - 234 - 7
• Spain - 1062 - 106
• Finland - 46 - 6
• France - 534 - 63
• Ireland - 118 - 19
• Malta - 49 - 1
• Portugal - 330 - 32
• Total - 2373 - 234

(...)


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

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

• Influenza A - 115 - 2139
  • A(H1) 2009 - 112 - 2012
  • A (subtyping not performed) - 3 - 113
  • A (H1) - ... - ...
  • A (H3) - ... - 14
• Influenza B - 6 - 75
• Other Pathogen - ... - 33
• Unknown - 59 - 1105
• Total - 180 - 3352

Table 7: Number of SARI cases by level of care and respiratory support, weeks 40/2010?6/2011

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

• No respiratory suppport available - ... - 1 - ... - ...
• No respiratory support necessary - 132 - 325 - 353 - ...
• Oxygen therapy - 69 - 108 - 287 - ...
• Respiratory support given unknown - 451 - 167 - 545 - 162
• Ventilator - 705 - 12 - 6 - 29
• Total - 1357 - 613 - 1191 - 191

(...)

Note: Other (O) 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: Link here
  • Influenza activity is still increasing.
  • Up to the end of week 6/2011 a cumulative total of 96 SARI patients with laboratory- confirmed influenza A(H1N1)2009 have been reported by intensive care units and there have been 12 influenza deaths.
• Denmark SSI Link here
  • Up to 14 February (week 6/2011), a cumulative total of 122 influenza patients have been reported by ICUs in Denmark with a median age of 54 years (and a range from 1 week to 83 years).
  • Nine patients were admitted to an ICU in week 6/2011 compared with 19 new admissions in week 5.
  • There is still pressure on the wards, reflected by the proportion of ICU beds used for influenza patients.
  • On Monday 14 February 2011 at 8:00 am, 33 influenza patients were in ICUs, corresponding to 9.6% of the total number of occupied ICU beds in the country.
  • This is compared with 10.0% the week before.
  • Of the ICU patients, 102 were diagnosed with influenza A, 38 of whom were reported to be further subtyped as subtype H1N1.
  • Twenty patients had an influenza B infection.
  • Eight patients with influenza A and two patients with influenza B received extracorporeal membrane oxygenation (ECMO).
  • Fifteen patients with confirmed influenza A and five with influenza B died.
  • Nineteen patients were reported to be previously healthy and for another 33 patients no underlying condition was reported.
  • For 70 patients one or more underlying conditions were described.
  • One influenza patient was reported to be pregnant.
• France: INVS Link Here
  • By week 6 in the sentinel network of hospitals Oscour 1 353 emergencies consultations for influenza-like illness had been reported with 90 hospitalisations, which is an increase from week 5.
  • In the national network of paediatric and adult ICUs the numbers have been decreasing since week 01/2011.
  • Considered cumulatively, 611 ICU influenza cases have been reported from ICUs with influenza A(H1N1)2009 predominating, and around 70% of cases being between 15 and 64 years of age.
  • A clinical risk factor is reported for most cases, conversely 37% of these severe cases were reported to have no identified risk factor.
  • In this network there have been 84 deaths reported, which represents 14% of reports.
• Ireland: HPSC influenza link here
  • For the 2010/2011 season to date (16 February 2011), 884 confirmed influenza cases have been hospitalised, of these 118 cases have been admitted to intensive care units and 18 deaths have been reported to HPSC.
  • At the peak, this represented 1.1/105 population cases requiring higher level (intensive) care but figures have declined considerably since then.
  • As of 16 February, 21 of the hospitalised cases remained in intensive care on 16 February compared with 31 a week before.
  • Eighty-six of the 118 intensive care cases (76%) had underlying medical conditions.
  • The underlying medical conditions include: chronic respiratory disease, chronic heart disease, immunosuppression, pregnancy, metabolic disorders and morbid obesity.
  • HPSC has been informed of 22 influenza-associated deaths to date this season (as of 16/02/2011).
  • Of the deaths: 17 had influenza A(H1N1)2009, one combined influenza A and B infections and three influenza B.
  • One death was in a patient in the 0?4 year age group, 16 patients were in the 15?64 year age group and five patients were aged 65 years and older.
• Malta: Link here
  • Situation unchanged.
• The Netherlands RIVM influenza link here
  • Between 4 October 2010 and week 6 (16 February), a cumulative total of 584 hospitalised patients were reported as infected with A(H1N1)2009 influenza virus.
  • There were 35 fatalities notified.
  • The largest numbers of hospitalised admissions with influenza have been in children in the age group 0?5 years.
  • Of the 584 patients with laboratory-confirmed influenza A (H1N1)2009 there were 32 pregnant women and 562 with information on the underlying condition.
  • Underlying conditions were reported in 46% of these.
  • This percentage rose to 53% of 447 patients over 5 years of age.
• Norway: FHI Link here
  • To 16 February the total of hospitalised influenza cases is 141 (admitted to ICU: 32).
  • By age group:
    • age 0?4 years hospitalised: 28 (to ICU: 3);
    • age 5?14 years hospitalised: 2 (to ICU: 1);
    • age 15?29 hospitalised: 19 (to ICU: 1);
    • age 30?64 years hospitalised: 83 (to ICU: 25) and
    • age 65 years and over hospitalised: 9 (in ICU: 2).
• Romania: Link here
  • Since the start of the season, influenza A(H1N1)2009 virus was detected in 39 of the 217 reported SARI cases, seven of these cases during week 06/2011, and influenza B virus was detected in 18 cases, four cases during week 06/2011.
  • From week 40/2010 to week 06/2011, 16 deaths were reported, eight positive for A(H1N1)2009 virus, one positive for B virus and one positive for Streptococcus pneumoniae.
  • During week 06/2011 two deaths were reported, one positive for A(H1N1)2009 virus, one positive for B virus.
  • None of the influenza positive SARI cases reported during the season had been vaccinated for influenza.
• Spain: ISCIII Influenza Link here
  • In Spain, information concerning severe illness due to influenza infection with associated admission to hospitals comes from a dedicated surveillance system developed during the 2009/2010 pandemic season.
  • Since week 40/2010 and up to week 06/2011 1 059 severe hospitalised confirmed influenza cases have been reported.
  • Severely affected cases were mostly in the 15 to 64 year age groups (66%).
  • Conversely 13% were less than five years old.
  • Of 944 cases with outcome information available 106 died (13% with no known risk factors).
  • Of the severe cases 662 had information available on the status of influenza vaccination for the 2010/2011 season and only 89 (13%) cases had been immunised.
  • Monovalent pandemic vaccines 2009 were reported to have been received by only 8% of hospitalised cases (41/504).
  • Among those hospitalised, 80% of the cases included were in groups which were recommended influenza vaccination (chronic diseases / pregnancy / obesity / being older than 60 years) and had not been vaccinated this season.
• UK: HPA Influenza Link and DH (England) Link
  • In week 7, the number of patients in England with confirmed or suspected influenza in critical care beds have declined further from its peak of nearly 800 (equivalent to 1.4 per 105 population) to around 70 cases on 17 February .
  • Up to 16 February 2011, 494 deaths have been reported in individual influenza cases from across the UK.
  • Ninety-three per cent of the cases with additional information were associated with A(H1N1) 2009 1% 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, 4% have been less than 5 years; 4% between 5 to 14 years; 72% from 15 to 64 years and 20% were 65 years or older.
  • Of those with available information 70% were in one of the clinical risk groups where vaccination is recommended, which includes pregnant women.
  • The most numerous reported clinical risk factors were underlying respiratory disease including asthma and immunosuppression.
  • Of cases with information on immunisation history 72% had not received the 2010 trivalent vaccine and 95% had not received the monovalent pandemic vaccine last season.
  • All-cause all-age deaths (due to multiple causes not just influenza) declined again in week 4 and is now well below the upper statistical limit of expected levels for this time of year.

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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[Giuseppe]

EuroFlu - Weekly Electronic Bulletin - Week 8 : 21/02/2011-27/02/2011 - 04 March 2011, Issue N? 392 (extract, edited)

EuroFlu - Weekly Electronic Bulletin - Week 8 : 21/02/2011-27/02/2011 - 04 March 2011, Issue N? 392 (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 8 : 21/02/2011-27/02/2011 - 04 March 2011, Issue N? 392

Influenza activity continues, but declines in many countries in the WHO European Region

• This issue is based on data reported in week 8/2011 by 44 Member States in the WHO European Region.
• Clinical influenza-like illness (ILI) and acute respiratory infection (ARI) activity are decreasing in 24 countries of the Region.
• According to sentinel surveillance, severe acute respiratory infection (SARI) shows declining trends in some countries, but remains above pre-season levels.
• 39% of sentinel specimens from patients with ILI and/or ARI, and 56% of specimens from sentinel SARI patients tested positive for influenza.
• Pandemic influenza A(H1N1) 2009 and influenza B continue to co-circulate in the Region.

Current situation - week 8/2011

During week 8/2011, ILI or ARI consultation rates decreased in all age groups in 24 of the 35 countries reporting clinical data.

Among 38 countries reporting on the geographical spread of influenza, most reported either widespread (15) or regional (7) activity, while 16 reported either sporadic or local activity.

Only 5 countries reported high-intensity influenza activity (compared with 9 countries last week), while 21 countries reported medium intensity and 11 countries, low intensity.

The impact of influenza on health care systems was low in 14 and moderate in 10 of the 24 countries reporting on this indicator.

Data from sentinel hospital-based surveillance for SARI were received from 9 countries (Armenia, Georgia, Kazakhstan, Kyrgyzstan, Romania, the Republic of Moldova, the Russian Federation, Serbia and Ukraine). Sentinel SARI hospitalizations have decreased substantially in Georgia, Kazakhstan, Kyrgyzstan and the Russian Federation, concurrent with overall declines in outpatient ARI or ILI consultation rates in these 4 countries.

In Romania, Serbia and Ukraine, SARI hospitalizations increased, as did the percentage of SARI specimens testing positive for influenza.

Among countries testing 10 or more sentinel SARI specimens, the percentage testing positive for influenza ranged from 40% in Kazakhstan to 67% in Ukraine with a median of 65% (mean: 53%).

Further information on the sentinel SARI surveillance systems represented in the EuroFlu bulletin can be found in the ?Overview of sentinel SARI systems in EuroFlu?.


Virological situation - week 8/2011

Pandemic influenza A(H1N1) 2009 was reported to be dominant in 7 countries and co-dominant with influenza B in 16 countries.

Influenza B was dominant in 7 countries.

Sentinel physicians collected 1611 respiratory specimens, of which 621 (39%) were positive for influenza virus: 273 (44%) were influenza A and 348 (56%) were influenza B.

Of the influenza A viruses, 243 were subtyped: 224 (92%) as pandemic A(H1) and 19 (8%) as A(H3).

In the 20 countries testing 20 or more sentinel specimens, influenza positivity ranged from 3% to 94%, with a median of 39% (mean: 39%).

In addition, 3639 non-sentinel specimens were reported positive for influenza: 2538 (70%) influenza A and 1101 (30%) influenza B.

Of the influenza A viruses, 2110 were subtyped: 2088 (99%) as pandemic A(H1) and 22 (1%) as A(H3).

Out of 226 sentinel SARI specimens collected during week 8/2011 (data from 8 countries), 126 (56%) tested positive for influenza: 65 (52%) were influenza A; 61 (48%) were influenza B.

Of the influenza A viruses, 41 were subtyped: 39 (95%) as pandemic A(H1), and 2 (5%) as A(H3).


Cumulative virological update - weeks 40/2010 - 8/2011

A total of 69 762 influenza virus detections were reported during this period, of which 50 098 (72%) were influenza A and 19 664 (28%) were influenza B.

Of the influenza A viruses, 38 790 were subtyped: 37 395 (96%) as pandemic A(H1), 1 394 (4%) as influenza A(H3) and 1 as influenza A(H1).

From week 40/2010 to week 8/2011, 1057 out of 3626 sentinel SARI specimens (29%) tested positive for influenza.

Of these influenza viruses, 526 (50%) were influenza A and 531 (50%) influenza B.

Of the influenza A viruses, 357 were subtyped: 331 (93%) as pandemic A(H1) and 26 (7%) as influenza A(H3).

Since week 40/2010, 2771 influenza viruses have been characterized antigenically:

• 1478 were A(H1) pandemic A/California/7/2009 (H1N1)-like;
• 1107 were B/Brisbane/60/2008-like (B/Victoria/2/87 lineage);
• 102 were A(H3) A/Perth/16/2009 (H3N2)-like;
• 83 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 384 influenza viruses:

• 164 belonged to the pandemic A/California/7/2009 A(H1N1) clade;
• 8 belonged to the pandemic A/Christchurch/16/2010 A(H1) clade;
• 38 belonged to the pandemic A/Hong Kong/2213/2010 A(H1) clade;
• 34 were reported as A(H1) pandemic not attributed to group category but belonging to the recently emerged A/England/142/2010 subgroup characterized by S185T substitution in the HA;
• 9 belonged to the A(H3) clade represented by A/Perth/16/2009;
• 6 belonged to the A(H3) clade represented by A/Victoria/208/2009;
• 20 belonged to the subgroup represented by A/Hong Kong/2121/2010 in the A/Victoria/208/2009 A(H3) clade;
• 9 belonged to the B/Bangladesh/3333/2007 clade (Yamagata lineage), and
• 96 to the B/Brisbane/60/2008 clade (Victoria lineage).

Since week 40/2010, 7 countries (Germany, Ireland, Italy, Norway, Spain, Switzerland and the United Kingdom) have screened 990 viruses for susceptibility to the neuraminidase inhibitors oseltamivir and zanamivir.

The United Kingdom analysed most of the viruses screened (671).

Out of the 924 pandemic A(H1N1) viruses that were tested, 892 were sensitive to both inhibitors and 32 viruses (3.5%) carried the NA H275Y mutation.

These 32 viruses were resistant to oseltamivir but remained sensitive to zanamivir.

3 influenza A(H3N2) viruses were tested and found to be sensitive to both inhibitors.

All of the 62 influenza B viruses tested for susceptibility to oseltamivir and the 63 tested for susceptibility to zanamivir were found to be sensitive.

All 115 pandemic influenza A(H1N1) 2009 viruses and 2 A(H3N2) viruses that were screened for susceptibility to adamantanes were found to be resistant.


Comment

Clinical ILI and ARI consultation rates continue to decline throughout most parts of the WHO European Region with most countries reporting medium activity.

A few countries, however, observe persisting and increasing clinical outpatient activity.

The percentage of sentinel specimens testing positive for influenza is declining overall, but remains high in several countries.

Whereas pandemic influenza A(H1N1) 2009 and influenza B currently co-dominate in northern and western Europe, pandemic influenza A(H1N1) 2009 is the dominant virus in the central and eastern parts of the Region.

Sentinel surveillance for SARI indicates that SARI hospitalizations are declining in the south-eastern part of the Region, while some countries in central Europe are observing increasing trends.

Prior to seasonal increases in influenza activity, a relatively large portion of sentinel SARI hospitalizations occurred in the group aged 0-4. With increases in influenza activity, however, particularly that associated with circulation of pandemic A(H1N1) 2009 viruses, there have been associated increases in the relative proportion of SARI hospitalizations in older children, young adults and adults.


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.

Further information on severe cases associated with influenza virus infections in the European Region can be found in the ECDC Weekly Influenza Surveillance Ove

(...)


Network comments (where available)

• Czech Republic
  • Up to end of week 8/2011 a cumulative total of 136 SARI patients with laboratory-confirmed influenza have been reported by intensive care units and there were 24 deaths.
  • Of those there were 4 SARI cases causes by Flu B including 1 death of 10-years-old boy in current week.
• Malta
  • situation stable
• Republic of Moldova
  • In two clinical specimens a coinfection of influenza B virus and A(H1N1)2009 virus was confirmed by Real Time PCR in the 8th week.
  • 173 clinical specimens from sentinel and non sentinel districts were examined by Real Time PCR, from which 122 specimens were positive: 84 specimens were positive for A(H1N1)2009; 14 specimens positive for A/H3; 23 specimens positive for Influenza B.
• Serbia
  • Serbia Sentinel SARI surveillance system in SERBIA: In week 08/2011, 48 SARI from all causes were reported.
  • Out of 43 SARI specimens collected in the week 08/2011, 27(62,8%) tested positive: 24 were influenza A and 3 were influenza B.
  • Of the influenza A viruses, 21 were subtyped as pandemic A(H1) and 3 as A(H3).
• Spain
  • In Spain information concerning severe illness due to influenza infection with associated admission to hospitals comes from a surveillance system developed during the 2009/2010 pandemic season specifically for this purpose.
  • Since week 40/2010 and up to week 08/2011 1271 severe hospitalised confirmed influenza cases have been reported.
  • Severely affected cases were mostly in the 15-64 year age groups (63%) and 15% were less than five years old and 18% were more than 64 years old.
  • Of them 25% with no know risk factors.
  • Of 1134 cases with outcome information 128 died (12% with no known risk factors).
  • Of the severe cases 834 had information available on the status of influenza vaccination for the 2010/2011 season and only 117 (14%) cases had been immunised.
  • Monovalent pandemic vaccines 2009 were reported to have been received for only 9% of hospitalised cases.
  • Eighty per cent of the cases included in the groups which were recommended influenza vaccination (chronic diseases / pregnancy / obesity / older than 60 years) had not been vaccinated this season

(...)
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[Giuseppe]

Weekly influenza surveillance overview, March 4, 2011 - Week 8 (ECDC, edited)

Weekly influenza surveillance overview, March 4, 2011 - Week 8 (ECDC, edited)


[Source: European Centre for Disease Prevention and Control (ECDC), full page: <cite cite="http://www.ecdc.europa.eu/en/publications/Publications/Forms/ECDC_DispForm.aspx?ID=656">Publications - 110304_SUR_Weekly_Influenza_Surveillance_Overview. pdf...</cite>. PDF document (LINK). Edited.]

Weekly influenza surveillance overview, March 4, 2011 - Week 8

Surveillance reports - 04 Mar 2011

Available as PDF in the following languages: English.

This document is free of charge.


ABSTRACT

Most European Union/European Economic Area countries are reporting regional or widespread influenza activity, with medium influenza-like illness (ILI)/acute respiratory infection (ARI) consultation rates and widespread activity.

Decreasing ILI/ARI trends were reported by the majority of countries.

The proportion of influenza virus-positive sentinel specimens has gradually decreased to 36%, after peaking in week 52/2010 at around 56%.

An increasing proportion of B viruses has been reported.

In week 08/2011, 58% of influenza virus detections were type A, and 42% were type B.

The latter are reported to be dominant now in a number of countries.

Of the 1139 subtyped influenza A viruses, 99% were A(H1N1)2009.

In week 08/2011, eleven countries reported 149 all-cause severe acute respiratory infection (SARI) and hospitalised confirmed influenza cases.

The latter were mostly due to influenza virus A(H1N1)2009 infection.

Numbers of influenza infections with severe outcome have decreased in western European Union countries that report these.

However, the number of cases remains high in Greece.

Apart from the Czech Republic, Romania and Slovakia, there is considerable uncertainty about cases with severe respiratory disease due to influenza in a number of other countries in central and eastern European Union countries because of limited hospital surveillance for influenza-associated cases.

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[Giuseppe]

EpiSouth Weekly Epi Bulletin ? N?155 - 3rd March 2011 ? 9th March 2011 (March 10 2011, edited)

EpiSouth Weekly Epi Bulletin ? N?155 - 3rd March 2011 ? 9th March 2011 (March 10 2011, edited)


[Source: Epi-South, full PDF document (LINK). Extract, edited.]

EpiSouth Weekly Epi Bulletin ? N?155 - 3rd March 2011 ? 9th March 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.


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

• EGYPT
  • On 5th March 2011, the Egyptian Ministry of Health reported 1 new human A(H5N1) case in Sharkia governorate (cf. map 1).
  • This 128th case is:
    • A 17 years old female
    • Onset of symptoms on 14th February 2011
    • She died on 28th February 2011
  • In Egypt, the last A(H5N1) human cases were reported to the Egyptian Ministry of Health on 25th February 2011 (cf. eWEB n?154).

• INDONESIA
  • On 2nd March 2011, the Indonesian health authorities reported to WHO a new human A(H5N1) case in West Java province (cf. map 2).
  • The case is:
    • A 26 years old female
    • Onset of symptoms on 30th January 2011
    • Hospitalized on 3rd February 2011
    • She died on 8th February 2011
    • Contacts with contaminated domestic birds has been documented.
  • In Indonesia, the last A(H5N1) human case was reported to the local health authorities on December 2010, in Bandung province (cf. eWEB n? 142).

Comments

• The A(H5N1) is enzootic in Indonesia.
• To date, 172 A(H5N1) cases including 142 deaths were reported to WHO in Indonesia.
• In the country, suspected A(H5N1) cases are regularly reported by various non official sources. In this respect, it is likely that the number of cases is under reported by national authorities.

(...)


Location: Israel / Palestine - Vietnam - Event: A(H5N1) ? Epizootic

• PALESTINE
  • On 3rd March 2011, the Palestinian health authorities reported to OIE a new avian A(H5N1) outbreak in domestic birds in Jenin, West Bank (cf. map 3).

• ISRAEL
  • On 7th March 2011, the Israeli health authorities reported a new avian A(H5N1) outbreak in Kibbutz Rosh Tsurim, an Israeli settlement located 8 km South West of Bethlehem (cf. map 3).
  • Control measures have been undertaken in both locations.

• VIETNAM
  • Between 23rd February and 9th March 2011, the Vietnamese Ministry of Agriculture and Rural Development reported several new A(H5N1) outbreaks in domestic birds in the North (Vinh Phuc, Thai Nguyen, Quang Ninh, Ha Nam), and in the Centre (Binh Dinh and Quang Ngai), cf. map 4.
  • The last A(H5N1) epizootics in the country were reported in February 2011, in Nam Dinh (North) and Kon Tum (Centre) provinces (cf. eWEB n? 153).
  • Considering that the occurrence of A(H5N1) avian outbreaks is frequent in Vietnam, from now on, the new outbreaks will be reported on the basis of larger geographic subdivisions, ie North, Centre, South, and no longer by provinces.
  • In Vietnam, the last A(H5N1) human case was reported to WHO in April 2010 (cf. eWEB n? 108).

Comments

• The last A(H5N1) epizootics reported by the Palestinian authorties were in Gaza and West Bank, in 2006.
• The last A(H5N1) epizootic reported by the Israeli authorties was in Hadarom province, (close to the Dead Sea), in May 2010 (cf.eWEB n? 112).
• To date, Israeli and Palestinian authorities haven?t reported any A(H5N1) human case.

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

Location: Yemen - Event: Chikungunya

• Since the end of 2010, an epidemic affects Hodeida governorate, in the South West of Yemen. To date, at least 1000 cases and 75 deaths have been reported.
• This epidemic is likely to be due to several aetiologies.
• Among the 15 hospitalized cases which were tested, 50% of them were positive to chikungunya.

Comments

• Chikungunya virus has been identified as one of the aetiologies. Nevertheless it cannot explain the high lethality which has been reported so far.
• While Yemen is located in the chikungunya risk area (as defined by WHO), it is the first formal identification of the virus in the country.
• The implementation of a sustainable transmission cycle in the country is very likely due to the presence of the vector (Aedes aegypti). Dengue outbreaks have already been reported in Yemen.
• Due to the location of the outbreak, in costal province, further spread to neighbouring countries cannot be excluded.

(...)


Location: USA - Event: Dengue

• On 2nd March 2011, the Miami-Dade county health authorities in Florida (USA) confirmed 1 autochthonous dengue case (cf. map 6).
• Vector control measures have been reinforced.

Comments

• It is the 2nd autochthonous dengue case reported in the county since November 2010 (cf. eWEB n?139)
• To date, the emergence of autochthonous cases hasn?t led to the implementation of a local sustainable transmission cycle, but the situation requires to be monitored carefully.

(...)

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[Giuseppe]

EuroFlu - Weekly Electronic Bulletin - Week 9 : 28/02/2011-06/03/2011 - 11 March 2011, Issue N? 393 (March 11 2011, edited)

EuroFlu - Weekly Electronic Bulletin - Week 9 : 28/02/2011-06/03/2011 - 11 March 2011, Issue N? 393 (March 11 2011, 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 9 : 28/02/2011-06/03/2011 - 11 March 2011, Issue N? 393

Continuing influenza activity despite declining trends in many countries

• This issue is based on data reported in week 9/2011 by 46 Member States in the WHO European Region.
• Influenza-like illness (ILI) and acute respiratory infection (ARI) activity are decreasing in 22 countries of the Region.
• According to sentinel surveillance, severe acute respiratory infection (SARI) shows declining trends in some countries, but remains above pre-season levels.
• 42% of sentinel specimens from patients with ILI and/or ARI, and 48% of specimens from sentinel SARI patients tested positive for influenza.
• Pandemic influenza A(H1N1) 2009 and influenza B continue to co-circulate in the Region.

Current situation - week 9/2011

During week 9/2011, of the 39 countries reporting on consultation rates for ILI and/or ARI, 22 reported decreases while 3 (Armenia, Iceland, and Ukraine) reported increases.

Among 41 countries reporting on the geographical spread of influenza, a majority reported either widespread (13) or regional (10) activity, while 17 reported either sporadic or local activity and one reported no activity.

High-intensity influenza activity was reported by Georgia only (compared with 5 countries last week), while 25 countries reported medium intensity and 14 countries, low intensity.

The impact of influenza on health care systems was severe in one country (Georgia), low in 14 and moderate in 7 of the 22 countries reporting on this indicator.

Data from sentinel hospital-based surveillance for SARI were received from 9 countries (Armenia, Georgia, Kazakhstan, Kyrgyzstan, Romania, the Republic of Moldova, the Russian Federation, Serbia and Ukraine).

Sentinel SARI hospitalizations have decreased substantially in Kazakhstan, Kyrgyzstan and the Republic of Moldova, concurrent with overall declines in outpatient ILI or ARI consultation rates in these 3 countries.

In Ukraine, SARI hospitalizations have increased in recent weeks and remain on a high level, concurrent with increase in ARI consultation rate.

In Romania and the Russian Federation, SARI hospitalizations have reached the highest levels observed in this season so far.

In the 7 countries testing 10 or more sentinel SARI specimens, the percentage testing positive for influenza ranged from 0% in Kyrgyzstan to 77% in Ukraine with a median of 45% (mean: 45%).

Further information on the sentinel SARI surveillance systems represented in the EuroFlu bulletin can be found in the ?Overview of sentinel SARI systems in EuroFlu?.


Virological situation - week 9/2011

Pandemic influenza A(H1N1) 2009 was reported to be dominant in 10 countries and co-dominant with influenza B in 16 countries.

Influenza B was dominant in 5 countries.

Sentinel physicians collected 1534 respiratory specimens, of which 640 (42%) were positive for influenza virus: 312 (49%) were influenza A and 328 (51%) were influenza B.

Of the influenza A viruses, 274 were subtyped: 260 (95%) as pandemic A(H1) and 14 (5%) as A(H3).

In the 21 countries testing 20 or more sentinel specimens, influenza positivity ranged from 10% to 91%, with a median of 45% (mean: 43%).

In addition, 3590 non-sentinel specimens were reported positive for influenza: 2707 (75%) influenza A and 883 (25%) influenza B.

Of the influenza A viruses, 2352 were subtyped: 2307 (98%) as pandemic A(H1) and 45 (2%) as A(H3).

Out of 206 sentinel SARI specimens collected during week 9/2011 (data from 8 countries), 98 (48%) tested positive for influenza: 53 (54%) were influenza A; 45 (46%) were influenza B.

Of the influenza A viruses, 36 were subtyped: 33 (92%) as pandemic A(H1), and 3 (8%) as A(H3).


Cumulative virological update - weeks 40/2010 - 9/2011

A total of 75 191 influenza virus detections were reported during this period, of which 54 203 (72%) were influenza A and 20 988 (28%) were influenza B.

Of the influenza A viruses, 42 466 were subtyped: 40 960 (96%) as pandemic A(H1), 1 505 (4%) as influenza A(H3) and 1 as influenza A(H1).

From week 40/2010 to week 9/2011, 1167 out of 3869 sentinel SARI specimens (30%) tested positive for influenza.

Of these influenza viruses, 591 (51%) were influenza A and 576 (49%) influenza B.

Of the influenza A viruses, 394 were subtyped: 365 (93%) as pandemic A(H1) and 29 (7%) as influenza A(H3).

Since week 40/2010, 3083 influenza viruses have been characterized antigenically:

• 1533 were A(H1) pandemic A/California/7/2009 (H1N1)-like;
• 1342 were B/Brisbane/60/2008-like (B/Victoria/2/87 lineage);
• 107 were A(H3) A/Perth/16/2009 (H3N2)-like; and
• 101 were B/Florida/4/2006-like (B/Yamagata/16/88 lineage).

Based on the genetic characterization of 434 influenza viruses:

• 187 belonged to the pandemic A/California/7/2009 A(H1N1) clade;
• 9 belonged to the pandemic A/Christchurch/16/2010 A(H1) clade;
• 38 belonged to the pandemic A/Hong Kong/2213/2010 A(H1) clade;
• 34 were reported as A(H1) pandemic not attributed to group category but belonging to the recently emerged A/England/142/2010 subgroup characterized by S185T substitution in the HA;
• 11 belonged to the A(H3) clade represented by A/Perth/16/2009;
• 6 belonged to the A(H3) clade represented by A/Victoria/208/2009;
• 28 belonged to the subgroup represented by A/Hong Kong/2121/2010 in the A/Victoria/208/2009 A(H3) clade;
• 11 belonged to the B/Bangladesh/3333/2007 clade (Yamagata lineage), and
• 110 to the B/Brisbane/60/2008 clade (Victoria lineage).

Since week 40/2010, 8 countries (Germany, Ireland, Italy, Netherlands, Norway, Spain, Switzerland and the United Kingdom) have screened 1217 viruses for susceptibility to the neuraminidase inhibitors oseltamivir and zanamivir.

The United Kingdom analysed most of the viruses screened (728).

Out of the 1134 pandemic A(H1N1) viruses that were tested, 1102 were sensitive to both inhibitors and 32 viruses (2.8%) carried the NA H275Y mutation.

These 32 viruses were resistant to oseltamivir but remained sensitive to zanamivir.

3 influenza A(H3N2) viruses were tested and found to be sensitive to both inhibitors.

All of the 80 influenza B viruses tested for susceptibility to oseltamivir and zanamivir were found to be sensitive.

All 174 pandemic influenza A(H1N1) 2009 viruses and 2 A(H3N2) viruses that were screened for susceptibility to adamantanes were found to be resistant.


Comment

ILI and ARI consultation rates continue to decline throughout most parts of the WHO European Region with most countries reporting medium or low activity. The percentage of sentinel specimens testing positive for influenza is declining overall, but remains high in several countries.

Whereas pandemic influenza A(H1N1) 2009 and influenza B currently co-dominate in northern and western Europe, pandemic influenza A(H1N1) 2009 is the dominant virus in the central and eastern parts of the Region.

Sentinel surveillance for SARI indicates that SARI hospitalizations are declining in the south-eastern part of the Region, while some countries in central Europe are observing increasing trends. Prior to seasonal increases in influenza activity, a relatively large portion of sentinel SARI hospitalizations occurred in the group aged 0-4. With increases in influenza activity, there have been associated increases in the relative proportion of SARI hospitalizations in older children, young adults and adults.


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.

Further information on severe cases associated with influenza virus infections in the European Region can be found in the ECDC Weekly Influenza Surveillance Overview.

(...)


Network comments (where available)

• Czech Republic
  • Up to end of week 9/2011 a cumulative total of 151 SARI patients with laboratory-confirmed influenza have been reported by intensive care units and there were 32 deaths.
  • Distribution by virus type and subtype is as follows:
    • A/H1N1- 144 SARI and 29 deaths
    • A/H3N2- 3 SARI and 2 deaths
    • B - 4 SARI and 1 death.
• Finland
  • Of the 54 samples tested during week 9, 5 were positive for parainfluenza virus type 3, and 9 for adenovirus.
  • Since week 40, 1706 laboratory-confirmed diagnoses of influenza A, and 1770 cases of influenza B have been reported to the national infectious disease registry.
    • Age group 0 - 4 years: 115 type A and 143 type B;
    • age group 5 - 14 years: 104 type A, 446 type B;
    • age group 15 - 64: 1411 type A, 1124 type B;
    • age group 65+: 76 type A, 57 type B.
• Greece
  • Two swabs were collected from an immunocompromized patient, the first on 10-Feb-11 and the second on 17-Feb-11 following tamiflu administration.
  • Both clinical samples were positive for A(H1N1)v, but only the second was confirmed by real time PCR to carry the H274Y mutation for tamiflu resistance.
  • NA sequence analysis is pending.
• Malta
  • situation stable
• Scotland
  • Increase in influenza activity small (33.1 per 100,000 population to 36).
  • Number of severely ill flu cases requiring ITU admission now remains low (111 as at 03 March 2011).
  • Total number of deaths related to flu reported to HPS now stands at 60 (as at 03 March 2011)
• Serbia
  • Serbia Sentinel SARI surveillance system in SERBIA:
    • In week 09/2011, 44 SARI from all causes were reported.
    • Out of 38 SARI specimens collected in the week 09/2011, 18(47,4%) tested positive: 14 were influenza A and 4 were influenza B.
    • Of the influenza A viruses, 12 were subtyped as pandemic A(H1) and 2 as A(H3).
• Spain
  • In Spain information concerning severe illness due to influenza infection with associated admission to hospitals comes from a surveillance system developed during the 2009/2010 pandemic season specifically for this purpose.
  • Since week 40/2010 and up to week 09/2011 1305 severe hospitalised confirmed influenza cases have been reported.
  • Severely affected cases were mostly in the 15-64 year age groups (64%) and 15% were less than five years old and 17% were more than 64 years old.
  • Of them 25% with no know risk factors.
  • Of 1157 cases with outcome information 139 died (13% with no known risk factors).
  • Of the severe cases 845 had information available on the status of influenza vaccination for the 2010/2011 season and only 121 (14%) cases had been immunised.
  • Monovalent pandemic vaccines 2009 were reported to have been received for 9% of hospitalised cases.
  • Most of severe and fatal cases included in the groups which were recommended influenza vaccination had not been vaccinated this season

(...)
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[Giuseppe]

Weekly influenza surveillance overview, March 11, 2011 - Week 9 (ECDC, March 11 2011)

Weekly influenza surveillance overview, March 11, 2011 - Week 9 (ECDC, March 11 2011)


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

Weekly influenza surveillance overview, March 11, 2011 - Week 9

Surveillance reports - 11 Mar 2011


Most European Union/European Economic Area countries are reporting regional or widespread influenza activity, with medium influenza-like illness (ILI)/acute respiratory infection (ARI) consultation rates.

Decreasing ILI/ARI trends were reported by the majority of countries.

An increasing proportion of B viruses has been reported.

In week 09/2011, 55.3% of influenza virus detections were type A, and 44.7% were type B.

The latter are reported to be dominant now in a number of countries.

Of the 784 subtyped influenza A viruses, 97.2% were A(H1N1)2009.

In week 09/2011, ten countries reported 119 cases of all-cause severe acute respiratory infection (SARI) and hospitalised confirmed influenza cases.

The latter were mostly due to influenza A(H1N1)2009 virus infection.

Numbers of influenza virus infections with severe outcome have decreased in western European Union countries that report these.

However, the number of cases remains high in Greece.

Apart from the Czech Republic, Romania and Slovakia, there is considerable uncertainty about cases with severe respiratory disease due to influenza in a number of central and eastern European Union countries because of limited hospital surveillance for influenza-associated cases.

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[Giuseppe]

EuroFlu - Weekly Electronic Bulletin - Week 10 : 07/03/2011-13/03/2011 - 18 March 2011, Issue N? 394 (Extract, edited)

EuroFlu - Weekly Electronic Bulletin - Week 10 : 07/03/2011-13/03/2011 - 18 March 2011, Issue N? 394 (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 10 : 07/03/2011-13/03/2011 - 18 March 2011, Issue N? 394

Declining trends in influenza activity in the WHO European Region

• This issue is based on data reported in week 10/2011 by 47 Member States in the WHO European Region.
• Influenza-like illness (ILI) and acute respiratory infection (ARI) activity has passed recent peaks in 37 countries of the Region.
• Sentinel hospitalizations for severe acute respiratory infection (SARI) are generally declining, but remain above pre-season levels in some countries.
• 42% of sentinel specimens from patients with ILI and/or ARI, and 46% of specimens from sentinel SARI patients tested positive for influenza.
• Pandemic influenza A(H1N1) 2009 and influenza B continue to co-circulate in the Region.

Current situation - week 10/2011

During week 10/2011, 23 countries reported a low intensity of influenza and 20 countries reported medium intensity.

Among 43 countries reporting on the geographical spread of influenza, a majority reported either sporadic (14) or local (13) activity, while 16 reported either regional or widespread activity.

The impact of influenza on health care systems was low in 20 and moderate in 5 of the 25 countries reporting on this indicator.

Clinical data also suggest decreasing influenza activity in much of the WHO European Region.

Of the 44 countries reporting on consultation rates for ILI and/or ARI, 18 countries reported decreases and 37 have passed apparent peaks in ILI or ARI clinical activity.

Data from sentinel hospital-based surveillance for SARI were received from 10 countries (Armenia, Georgia, Kazakhstan, Kyrgyzstan, Malta, the Republic of Moldova, Romania, the Russian Federation, Serbia and Ukraine).

During week 10/2011, sentinel SARI hospitalizations decreased substantially in Kazakhstan, Kyrgyzstan and the Russian Federation.

In Georgia, the Republic of Moldova, Romania, Serbia and Ukraine, SARI hospitalizations have decreased compared to recent weeks, but they remain above pre-season levels.

In the 4 countries (Georgia, the Republic of Moldova, Romania and the Russian Federation) testing 10 or more sentinel SARI specimens, the percentage testing positive for influenza ranged from 30% in the Russian Federation to 63% in Romania.

Further information on the sentinel SARI surveillance systems represented in the EuroFlu bulletin can be found in the ?Overview of sentinel SARI systems in EuroFlu?.


Virological situation - week 10/2011

Pandemic influenza A(H1N1) 2009 was reported to be dominant in 7 countries and co-dominant with influenza B in 12 countries. Influenza B was dominant in 6 countries.

Sentinel physicians collected 1107 respiratory specimens, of which 459 (42%) were positive for influenza virus: 212 (46%) were influenza A and 247 (54%) were influenza B.

Of the influenza A viruses, 194 were subtyped: 180 (93%) as pandemic A(H1) and 14 (7%) as A(H3).

In the 18 countries testing 20 or more sentinel specimens, influenza positivity ranged from 0% to 88%, with a median of 31% (mean: 38%).

In addition, 2318 non-sentinel specimens were reported positive for influenza: 1518 (65%) influenza A and 800 (35%) influenza B.

Of the influenza A viruses, 1248 were subtyped: 1216 (97%) as pandemic A(H1) and 32 (3%) as A(H3).

Out of 145 sentinel SARI specimens collected during week 10/2011 (data from 9 countries), 67 (46%) tested positive for influenza: 39 (58%) were influenza A; 28 (42%) were influenza B.

Of the influenza A viruses, 31 were subtyped: 25 (81%) as pandemic A(H1) and 6 (19%) as A(H3).


Cumulative virological update - weeks 40/2010 - 10/2011

A total of 77 832 influenza virus detections were reported during this period, of which 55 808 (72%) were influenza A and 22 024 (28%) were influenza B.

Of the influenza A viruses, 43 910 were subtyped: 42 419 (97%) as pandemic A(H1), 1490 (3%) as influenza A(H3) and 1 as influenza A(H1).

From week 40/2010 to week 10/2011, 1312 out of 4583 sentinel SARI specimens (29%) tested positive for influenza.

Of these influenza viruses, 707 (54%) were influenza A and 605 (46%) influenza B.

Of the influenza A viruses, 478 were subtyped: 437 (91%) as pandemic A(H1) and 41 (9%) as influenza A(H3).

Since week 40/2010, 3384 influenza viruses have been characterized antigenically:

• 1668 were A(H1) pandemic A/California/7/2009 (H1N1)-like;
• 1482 were B/Brisbane/60/2008-like (B/Victoria/2/87 lineage);
• 112 were A(H3) A/Perth/16/2009 (H3N2)-like;
• 121 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 485 influenza viruses:

• 207 belonged to the pandemic A/California/7/2009 A(H1N1) clade;
• 10 belonged to the pandemic A/Christchurch/16/2010 A(H1) clade;
• 46 belonged to the pandemic A/Hong Kong/2213/2010 A(H1) clade;
• 41 were reported as A(H1) pandemic not attributed to group category but belonging to the recently emerged A/England/142/2010 subgroup characterized by S185T substitution in the HA;
• 11 belonged to the A(H3) clade represented by A/Perth/16/2009;
• 7 belonged to the A(H3) clade represented by A/Victoria/208/2009;
• 29 belonged to the subgroup represented by A/Hong Kong/2121/2010 in the A/Victoria/208/2009 A(H3) clade;
• 16 belonged to the B/Bangladesh/3333/2007 clade (Yamagata lineage), and
• 118 to the B/Brisbane/60/2008 clade (Victoria lineage).

Since week 40/2010, 8 countries (Germany, Ireland, Italy, Netherlands, Norway, Spain, Switzerland and the United Kingdom) have screened 1227 viruses for susceptibility to the neuraminidase inhibitors oseltamivir and zanamivir. The United Kingdom analysed most of the viruses screened (728).

Out of the 1144 pandemic A(H1N1) viruses that were tested, 1112 were sensitive to both inhibitors and 32 viruses (2.8%) carried the NA H275Y mutation. These 32 viruses were resistant to oseltamivir but remained sensitive to zanamivir. 3 influenza A(H3N2) viruses were tested and found to be sensitive to both inhibitors. All of the 80 influenza B viruses tested for susceptibility to oseltamivir and zanamivir were found to be sensitive. All 174 pandemic influenza A(H1N1) 2009 viruses and 2 A(H3N2) viruses that were screened for susceptibility to adamantanes were found to be resistant.


Comment

ILI and ARI consultation rates continue to decline throughout most parts of the WHO European Region with all countries reporting medium or low activity during week 10/2011. The percentage of sentinel ILI, ARI and SARI specimens testing positive for influenza has also declined in recent weeks in many countries, but influenza activity continues. While pandemic influenza A(H1N1) 2009 and influenza B currently co-dominate in northern, western and central Europe, pandemic influenza A(H1N1) 2009 is the dominant virus in eastern part of the Region.


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.

Further information on severe cases associated with influenza virus infections in the European Region can be found in the ECDC Weekly Influenza Surveillance Overview.

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Network comments (where available)

• Czech Republic
  • Up to end of week 10/2011 a cumulative total of 157 SARI patients with laboratory-confirmed influenza have been reported by intensive care units and there were 36 deaths.
  • Distribution by virus type and subtype is as follows:
    • A/H1N1- 150 SARI and 33 deaths
    • A/H3N2- 3 SARI and 2 deaths
    • B- 4 SARI and 1 death.
• Malta
  • situation stable
• Serbia
  • Serbia Sentinel SARI surveillance system in SERBIA: In week 10/2011, 24 SARI from all causes were reported.
  • Out of 17 SARI specimens collected in the week 10/2011, 9 (52,9%) tested positive: 6 were influenza A and 3 were influenza B.
  • Of the influenza A viruses, 4 were subtyped as pandemic A(H1) .
• Spain
  • In Spain information concerning severe illness due to influenza infection with associated admission to hospitals comes from a surveillance system developed during the 2009/2010 pandemic season specifically for this purpose.
  • Since week 40/2010 and up to week 10/2011 1330 severe hospitalised confirmed influenza cases have been reported.
  • Severely affected cases were mostly in the 15-64 year age groups (64%) and 15% were less than five years old and 17% were more than 64 years old.
  • 25% of them with no known risk factors.
  • Of 1323 cases with outcome information 146 died (13% with no known risk factors).
  • Of the severe cases 865 had information available on the status of influenza vaccination for the 2010/2011 season and only 127 (15%) cases had been immunised.
  • Monovalent pandemic vaccines 2009 were reported to have been received for 9% of hospitalised cases.
  • Most of severe and fatal cases included in the groups which were recommended influenza vaccination had not been vaccinated this season

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