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Weekly influenza surveillance overview - 17 Dec 2010: 73 percent SARI cases seen in children <7 years of age, all had no underlying conditions.

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  • Weekly influenza surveillance overview - 17 Dec 2010: 73 percent SARI cases seen in children <7 years of age, all had no underlying conditions.

    ECDC Weekly influenza surveillance overview - 17 December 2010 (Extract, edited)


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

    SURVEILLANCE REPORT

    Weekly influenza surveillance overview - 17 December 2010


    Main surveillance developments in week 49/2010 (06 Dec 2010 ? 12 Dec 2010)

    This first page contains the main developments of this week and can be printed separately or together with the more detailed information following.
    • During week 49/2010, 24 of the 25 reporting countries and the UK (Northern Ireland, Scotland and Wales) experienced influenza activity of low intensity while the UK (England) reported medium intensity and activity above the baseline.
    • Fourteen countries reported an increasing trend.
    • Several severe cases of influenza and deaths have been reported in the last three weeks in the UK.
    • During week 49/2010, 22% of sentinel specimens were positive for influenza.
    • Of the 347 influenza viruses detected during week 49/2010, 234 (67%) were type A, the majority of which were A(H1N1) 2009, 113 (33%) were type B and a small number A(H3).
    • The circulating viruses detected to date, have been similar to the current vaccine viruses. This indicates that the annual influenza epidemics are starting in Europe and that at present they are dominated by influenza A(H1N1) 2009 and B viruses.
    • Eighty-six SARI cases were reported by two countries (Belgium and Romania) during week 49/2010. For all of these cases, the causative pathogen was unknown.
    • Seventy-three percent of the SARI cases were seen in children younger than seventeen years of age, all of whom had no underlying conditions.


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

    Twenty four of the 25 reporting countries and the UK (Northern Ireland, Scotland and Wales) experienced influenza activity of low intensity while the UK (England) reported medium intensity. Fourteen countries reported increasing trend.


    Virological surveillance:

    During week 49/2010, 22.1% of sentinel specimens were positive for influenza. Of the 347 influenza viruses detected during week 49/2010, 234 (67%) were type A and 113 (33%) were type B.


    Hospital surveillance of severe acute respiratory infection (SARI):

    During week 49/2010, 86 SARI cases were reported, four of which had symptom onset during this week.


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

    Twenty four of the 25 reporting countries and the UK (Northern Ireland, Scotland and Wales) experienced influenza activity of low intensity.

    Only the UK (England) reported medium intensity and activity above the baseline (Table 1, Map 1).

    Sporadic activity was reported by 13 countries and the UK (Northern Ireland, Scotland and Wales).

    Norway reported local spread while Finland and Italy reported regional spread.

    The UK (England) has reported widespread geographic spread. Eight countries reported no activity (Table 1, Map 2).

    Fourteen countries reported increasing trends in week 49/2010. Nine countries reported stable trends while Spain reported a decreasing trend. (Table 1, Map 2).

    (...)


    Table 1: Epidemiological and virological overview by country, week 49/2010

    [Country - Intensity - Geographic spread - Trend - No. of sentinel swabs - Dominant type - Percentage positive* - ILI per 100.000 - ARI per 100.000]
    • Austria - Low - No activity - Unknown (no information available) - 6 - None - 16.7 - ... - 25.1
    • Belgium - Low - Sporadic - Increasing - 29 - B - 31.0 - 67.5 - 1027.9
    • Bulgaria - Low - No activity - Increasing - 39 - None - 0.0 - ... - 963.0
    • Cyprus - ... - ... - ... - .. - ... - 0.0 - ... - ...
    • Czech Republic - ... - ... - ... - ... - ... - 0.0 - ... - ...
    • Denmark - Low - No activity - Stable - 8 - None - 37.5 - 78.7 - ...
    • Estonia - Low - Sporadic - Increasing - 26 - None - 3.8 - 6.4 -309.5
    • Finland - Low - Regional - Increasing 34 - swoAH1N1 - 38.2 - ... - ...
    • France - Low - Sporadic - Increasing - 75 - None - 20.0 - ... - 1908.7
    • Germany - Low - Sporadic - Increasing - 39 - None - 2.6 - ... - 1109.8
    • Greece - Low - No activity - Stable - 2 - None - 0.0 - 53.4 - ...
    • Hungary - Low - No activity - Increasing - 66 - None - 0.0 - 122.5 - ...
    • Iceland - ... - ... - ... - ... - ... - 0.0 - ... - ...
    • Ireland - Low - Sporadic - Increasing - 6 - AH1v - 83.3 - 14.4 - ...
    • Italy - Low - Regional - Increasing - 6 - None - 0.0 - 150.8 - ...
    • Latvia - Low - Sporadic - Stable - 0 - None - 0.0 - 0.0 - 1000.1
    • Lithuania - Low - No activity - Increasing - ... - ... - 0.0 - 1.7 - 533.6
    • Luxembourg - Low - Sporadic - Stable - 6 - None - 33.3 - ...* - ...*
    • Malta - ... - ... - ... - ... - ... - 0.0 - ... - ...
    • Netherlands - Low - No activity - Stable - 11 - None - 9.1 - 37.6 - ...
    • Norway - Low - Local - Increasing - 8 - B - 62.5 - 41.9 - ...
    • Poland - Low - Sporadic - Stable - 11 - None - 18.2 - 62.6 - ...
    • Portugal - Low - Sporadic - Increasing - 5 - B - 40.0 - 35.0 - ...
    • Romania - Low - No activity - Increasing - 35 - None - 0.0 - 18.9 - 759.2
    • Slovakia - Low - Sporadic - Stable - 6 - None - 0.0 - 199.9 - 1793.0
    • Slovenia - Low - Sporadic - Stable - 12 - None - 8.3 - 1.3 - 1134.9
    • Spain - Low - Sporadic - Decreasing - 26 - None - 19.2 - 13.6 - ...
    • Sweden - Low - Sporadic - Stable - 15 - B, AH1v - 6.7 - 4.9 - ...
    • UK - England - Medium - Widespread - Increasing - 183 - A, B - 42.1 - 34.6 - 666.4
    • UK - Northern Ireland - Low - Sporadic - Increasing - 6 - AH1N1 - 16.7 - 29.2 - 406.7
    • UK - Scotland - Low - Sporadic - Increasing - 6 - None - 33.3 - 1.1 - 160.6
    • UK - Wales - Low - Sporadic - Increasing - ... - ... - 0.0 - 22.5 - ...
    • Europe - ... - ... - ... - 666 - ... - 22.1 - ... - ...

    *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

    UK (England):

    The general practitioner consultation rate threshold has been breached, calls to NHS Direct (nurse-led medical helpline) for flu-related illnesses are increasing, and many (mainly school) outbreaks?of influenza H1N1 (2009) and influenza B?have been reported, indicating influenza transmission in the community.

    Several severe cases of influenza have been reported in the last three weeks resulting in an increase in ITU-bed occupancy and in the provision of beds used for Extra-Corporeal Membrane Oxygenation (ECMO).

    The majority of these patients are younger than 65 years of age.

    Further information can be found on the Health Protection Agency website: (LINK)


    UK (Scotland):

    A small number of severe acute respiratory infections (SARI) resulting in intensive care admission in individuals with confirmed influenza A (H1N1) 2009 virus.


    Description of the system

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


    Virological surveillance - Weekly analysis ? virology

    In week 49/2010, 24 countries reported virological data.

    Sentinel physicians collected 666 swabs with an increased percentage (22%) of specimens testing positive for influenza virus compared to 13% last week (Tables 1 and 2, Figure 3).

    Belgium, Finland, France, Spain and the UK (England) reported 31, 38, 20, 19 and 42% positive specimens, respectively (Table 1).

    In addition, 200 non-sentinel source specimens (i.e. specimens collected for diagnostic purpose in hospitals) were reported positive for influenza virus.

    Of the 347 influenza viruses detected during week 49/2010, 234 (67%) were type A and 113 (33%) were type B.

    The dominant virus types varied between countries: Belgium, Norway and Portugal reported predominantly influenza B virus; Finland, Ireland and the UK (Northern Ireland) reported A(H1N1) 2009; Sweden a mixture of the previous two; and the UK (England) a mixture of influenza A and B viruses (Table 1). Of the 127 sentinel influenza A viruses that were sub-typed, 121 (95%) were A(H1N1) 2009 and six (4.7%) were A(H3) viruses (Table 2).

    Since week 40/2010, of the 981 influenza detections in sentinel and non-sentinel specimens, 633 (65%) were influenza A and 348 (35%) were influenza B viruses.

    Of 367 influenza A viruses sub-typed, 314 (86%) were A(H1N1) 2009 and 53 (14%) were A(H3) viruses (Table 2).

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

    Since week 40/2010, 77 influenza viruses from sentinel and non-sentinel specimens have been characterised antigenically (Figure 4): 37 as A/California/7/2009 (H1N1)-like; 13 as A/Perth/16/2009 (H3N2)-like; 26 as B/Brisbane/60/2008-like (Victoria lineage); and one as B/Florida/4/2006-like (Yamagata lineage).

    More details on circulating viruses can be found in the report prepared by the Community Network of Reference Laboratories (CNRL) coordination team.

    In week 49/2010, respiratory syncytial virus detections were reported by 16 countries, similar to last week?s levels (Figure 5).


    Weekly Cumulative influenza virus detections by type, subtype and surveillance system, weeks 40/2010-49/2010.

    [VIrus Type/Subtype - Current Period: Sentinel - Non-sentinel / Season: Sentinel - Non-sentinel]
    • Influenza A - 91 - 143 / 239 - 394
      • A (pandemic H1N1) - 79 - 42 / 192 - 122
      • A (subtyping not performed) - 10 - 97 / 19 - 247
      • A (not subtypable) - 0 - 0 / 0 - 0
      • A (H3) - 2 - 4 / 28 - 25
      • A (H1) - 0 - 0 / 0 - 0
    • Influenza B - 56 - 57 / 149 - 199
    • Total Influenza - 147 - 200 / 388 - 593

    Note: A(pandemic H1N1), A(H3) and A(H1) include both N-subtyped and non- N-subtyped viruses.

    (...)


    Description of the system

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

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


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

    During weeks 40?49/2010, a total of 368 SARI cases were reported to TESSy (Table 3).

    In week 49/2010, 86 SARI cases were reported: 74 in Belgium and 12 in Romania.

    Four of these SARI cases had symptom onset during week 49/2010.

    The gender ratio (male/female) was 1.3 (Table 4) and no information was available regarding the
    possible causative pathogens (Table 5).

    Eleven cases were admitted to an intensive care unit and eight cases needed respiratory support (Table 7).

    The vaccination status of fifteen patients was known and three were vaccinated (Table 8). Of the remaining twelve patients who were not vaccinated, six had no underlying conditions and four were infants less than four years old.

    Sixty three (73%) of the SARI cases were seen in children below seventeen years of age, all without underlying conditions, and 43 of these were in children below two years of age (Table 9).

    The only fatal case reported, was not related to influenza infection (Table 3).


    Table 3: Cumulative number of SARI cases, weeks 40/2010?week 49/2010

    [Country - Number of cases - Incidence of SARI cases per 100,000 population - Number of fatal cases reported - Incidence of fatal cases per 100,000 population - Estimated population covered]
    • Belgium - 312 - ... - ... - ... - ...
    • Romania - 55 - 0.86 - 1 - 0.02 - 6.413.821
    • Slovakia - 1 - ... - ... - ... - ...
    • Total - 368 - ... - 1 - ... - 6.413.821

    (...)


    Table 4: Number of SARI cases by age and gender, week 49/2010

    [Age groups - Male - Female]
    • Under 2 - 28 - 19
    • 2-17 - 12 - 11
    • 18-44 - 2 - 2
    • 45-59 - 1 - 4
    • >=60 - 6 - 1
    • Total - 49 - 37


    Table 5: Number of SARI cases by influenza type and subtype, week 49/2010

    [Virus type/subtype - Number of cases during current week - Cumulative number of cases since the start of the season]
    • Influenza A - ... - ...
      • A (H1N1) 2009 - ... - ...
      • A(subtyping not performed) - ... - ...
      • A(H3) - ... - ...
      • A(H1) - ... - ...
    • Influenza B - ... - ...
    • Unknown - 79 - 345
    • Total - 86 - 368


    Table 6: Number of SARI cases by antiviral treatment, week 49/2010

    [Antiviral treatment - Number of patients who received prophylaxis - Number of patients who received anti-viral treatment]
    • Oseltamivir - ... - 1
    • Unknown - 74 - 74
    • None - 12 - 11
    • Total - 86 - 86


    Table 7: Number of SARI cases by level of care and respiratory support, week 49/2010

    [Respiratory support - ICU - Inpatient ward - Other - Unknown]
    • No respiratory support necessary - 3 - 3 - 51 - ...
    • Oxygen therapy - 5 - 6 - 11 - ...
    • Ventilator - 3 - 1 - 3 - ...


    Table 8: Number of SARI cases by vaccination status, week 49/2010

    [Vaccination Status - Number Of Cases - Percentage of cases]
    • Not vaccinated - 12 - 14
    • Seasonal vaccination - 3 - 4
    • Unknown - 71 - 82.6
    • TOTAL - 86 - ...

    (...)


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


    Table 9: Number of underlying conditions in SARI cases by age group, week 49/2010

    [Underlying condition/risk factor - Infant below 2 years - 2-17 years - 18-44 years - 45-59 years - >=60 years]
    • Chronic heart disease - ... - ... - ... - ... - 2
    • HIV/other immune deficiency - ... - ... - ... - 2 - ...
    • Liver-related condition - ... - ... - 1 - ... - ...
    • No underlying condition - 43 - 20 - 3 - 1 - ...
    • Other (please specify separately) - 4 - 3 - ... - 1 - 3
    • Obesity (BMI between 30 and 40) - ... - ... - ... - 1 - 2


    Table 10: Additional clinical complications in SARI cases by age group, week 49/2010

    [Additional clinical complications - Infant below 2 years - 2-17 years - 18-44 years - 45-59 years - >=60 years]
    • Acute respiratory distress syndrome - 4 - 1 - 1 - ... - 1
    • Bronchiolitis - 1 - ... - ... - ... - ...
    • None - ... - 1 - ... - ... - 1
    • Pneumonia (secondary bacterial infection) - ... - ... - 2 - ... - ...
    • Unknown - 42 - 21 - 1 - 5 - 5


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

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

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

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