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EuroFlu - Weekly Electronic Bulletin - Week 8 : 17/02/2014-23/02/2014 - 28 February 2014, Issue No. 519 (edited)

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  • EuroFlu - Weekly Electronic Bulletin - Week 8 : 17/02/2014-23/02/2014 - 28 February 2014, Issue No. 519 (edited)

    [Source: EuroFlu, full page: (LINK). Edited.]

    EuroFlu - Weekly Electronic Bulletin - Week 8 : 17/02/2014-23/02/2014 - 28 February 2014, Issue No. 519

    Varying levels of influenza activity across Europe

    Summary, week 08/2014
    • Consultation rates for influenza-like illness (ILI) and/or acute respiratory infection (ARI) continued to increase in the central, northern and eastern parts of the WHO European Region, but decreased in some southern countries, where the season started earlier.
    • Based on the results of outpatient and hospital surveillance, influenza A(H1N1)pdm09 and A(H3N2) viruses continued to co-circulate in the Region, with A(H1N1)pdm09 remaining predominant in northern Europe while A(H3N2) predominated in most of the countries in eastern Europe.

    The EuroFlu bulletin describes and comments on influenza activity in the 53 Member States in the WHO European Region to provide information to public health specialists, clinicians and the public on the timing of the influenza season, the spread of influenza, the prevalence and characteristics of circulating viruses (type, subtype and lineage) and severity.

    For a description of influenza surveillance in the WHO European Region see below.


    Virological surveillance for influenza

    During week 08/2014, 15 591 specimens from sentinel and non-sentinel sources were tested for influenza, 3466 (22%) of which were positive: 3345 (97%) influenza A and 121 (3%) influenza B (Fig. 1 and 2).


    Influenza A has remained the dominant virus type across the Region since week 40/2013.

    Of the 2065 influenza A viruses that were subtyped during week 08/2014, 1237 (60%) were A(H1N1)pdm09 and 828 (40%) A(H3N2) ? a distribution similar to that in the previous week (Fig. 2a).

    Since the beginning of weekly monitoring (week 40/2013), sentinel and non-sentinel sources have yielded 23 164 influenza detections: 22 209 (96%) were influenza A and 955 (4%) influenza B viruses (Fig. 2b).

    Of the 16 029 influenza A viruses that have been subtyped, 9884 (62%) were A(H1N1)pdm09 and 6145 (38%) were A(H3N2).

    In addition, since week 40/2013, the lineage of 100 influenza B viruses has been determined: 91 (91%) belonged to the B/Yamagata lineage (the lineage of the B virus recommended by WHO for inclusion in trivalent seasonal influenza vaccines) and 9 (9%) to B/Victoria.



    For week 08/2014, 29 countries reported influenza A as the dominant type.
    Turkey reported influenza B as dominant, despite having a low level of detections (Map 1 and country table).

    In countries providing data on dominant subtypes, influenza A(H3N2) was reported as dominant in 10 countries (Armenia, Georgia, Germany, Ireland, Italy, Luxembourg, the Netherlands, the Republic of Moldova, Slovenia and Ukraine), while 11 countries (Bulgaria, Denmark, Estonia, Finland, Greece, Iceland, Kazakhstan, Norway, Spain, Sweden and the United Kingdom (Wales)) reported A(H1N1)pdm09 as dominant.

    6 countries (Albania, Belgium, France, Latvia, the Russian Federation and Switzerland) reported A(H1N1)pdm09 and A(H3N2) as co-dominant.

    Virus strain characterizations

    Circulating influenza viruses are assessed each season for their antigenic and genetic characteristics, to determine the extent of their antigenic similarity to the viruses included in the seasonal influenza vaccine, and determine the prevalence of mutations that affect pathogenicity or are associated with susceptibility to antiviral drugs.

    For the 2013/2014 northern hemisphere influenza season, WHO recommended inclusion of A/California/7/2009 (H1N1)pdm09-like, A/Texas/50/2012 (H3N2)-like and B/Massachusetts/2/2012-like (Yamagata lineage) viruses in vaccines (see the WHO headquarters web site).

    The WHO Consultation on the Composition of Influenza Virus Vaccines for the Northern Hemisphere 2014?2015 took place in week 7/2014, and the WHO expert group recommended no change from the vaccine composition for the 2013?2014 season. (see the WHO headquarters web site).

    Since week 40/2013, 597 influenza viruses characterized antigenically by 13 countries (the Czech Republic, Denmark, Finland, Germany, Latvia, the Netherlands, Norway, Portugal, Romania, the Russian Federation, Slovakia, Switzerland and the United Kingdom (England)) corresponded with the viruses recommended by WHO for inclusion in the current northern hemisphere seasonal influenza vaccine (Fig. 3).

    14 countries (Belgium, the Czech Republic, Denmark, Finland, Germany, Greece, Ireland, the Netherlands, Norway, Portugal, the Russian Federation, Spain, Sweden and Switzerland) have characterized 480 influenza viruses genetically (Fig. 4).


    # Included in the WHO-recommended composition of influenza virus vaccines for use in the 2013/2014 northern hemisphere influenza season.

    * Included in the WHO-recommended composition of influenza virus vaccines for use in the 2014 southern hemisphere influenza season.

    Monitoring of susceptibility to antiviral drugs

    Since week 40/2013, 8 countries (Greece, the Netherlands, Norway, Portugal, Spain, Sweden, the Russian Federation and the United Kingdom (England)) have screened 530 viruses for susceptibility to the neuraminidase inhibitors oseltamivir and zanamivir.

    Of the 400 A(H1N1)pdm09 viruses tested, 398 showed susceptibility to both drugs.

    2 viruses carrying the neuraminidase H275Y amino acid substitution, causing resistance to oseltamivir, were detected in the United Kingdom in hospitalized patients treated with oseltamivir.

    Of the 105 influenza A(H3N2) viruses tested, 104 showed susceptibility to both drugs.

    The remaining virus, detected in the United Kingdom in a hospitalized immunocompromised patient treated with oseltamivir, carried the neuraminidase E119V amino acid substitution, and showed reduced inhibition by oseltamivir but normal inhibition by zanamivir.

    All 25 influenza B viruses tested showed susceptibility to both oseltamivir and zanamivir.

    So far, there is no indication of increased resistance to the neuraminidase inhibitors during the winter of 2013?2014.

    All 84 influenza A(H1N1)pdm09 and 66 influenza A(H3N2) viruses screened for susceptibility to adamantanes were found to be resistant.

    Outpatient surveillance for influenza-like illness (ILI) and/or acute respiratory infection (ARI)

    During week 08/2014, most European countries continued to report low-intensity influenza activity (Map 2), with fewer countries reporting increasing trends than in previous weeks (Map 4). Regarding geographic spread, influenza activity remained predominantly regional or widespread all over the Region (Map 3).

    During week 08/2014, consultation rates stabilized in most countries in the Region. Of the 22 countries with established national thresholds, the consultation rates remained above or at threshold levels in most.

    Nevertheless, consultation rates continued to decrease in the southern part of the Region (Bulgaria, Italy, Portugal and Spain), where the influenza season started earlier.


    During week 08/2014, 646 sentinel specimens tested positive for influenza.

    The percentage of sentinel ILI/ARI specimens testing positive for influenza in week 08/2014 remained much lower than in the same week in the 4 preceding seasons (Fig. 5).


    During week 08/2014, 646 (32%) of the 2036 specimens collected from sentinel sources tested positive for influenza, the majority being influenza A(H3N2) (Fig. 6a). Click here for a detailed overview in a table format.

    Hospital surveillance for SARI

    For surveillance of severe disease due to influenza, the number of SARI hospitalizations associated with influenza infection slightly increased from those in previous weeks, in association with increasing influenza activity in the eastern part of the Region. Most SARI cases were reported in those aged 0?4 years (Fig. 7).


    During week 08/2014, 920 SARI cases were reported; 87 (32%) of the 275 SARI samples collected in Albania, Armenia, Belarus, Georgia, Kazakhstan, Kyrgyzstan, the Republic of Moldova, Romania, the Russian Federation, Serbia and Ukraine tested positive for influenza A, the majority being A(H3N2), in line with the results of outpatient sentinel surveillance (Fig. 8a). Click here for a detailed overview in table format.


    For week 8/2014, 7 countries (Finland, France, Ireland, Romania, Spain, Sweden and the United Kingdom) reported 213 hospitalized, laboratory-confirmed influenza cases, including 112 cases admitted to intensive care units (ICUs).

    Since week 40/2013, 7 countries have reported 3024 hospitalized, laboratory-confirmed influenza cases: 2997 (99%) were related to influenza virus type A infection and 27 (1%) to type B infection.

    A total of 2013 influenza A viruses has been subtyped; 1573 (78%) were A(H1)pdm09 and 440 (22%) were A(H3).

    7 countries reported a total of 254 fatal influenza cases. All were associated with type A virus infection and 191 of the viruses were subtyped: 157 (82%) as A(H1N1)pdm09 and 34 (18%) as A(H3).

    SARI and hospitalized laboratory-confirmed influenza cases reported to the European Centre for Disease Prevention and Control (ECDC) differ in that the former include a higher proportion of influenza B and a lower proportion of influenza A(H1N1)pdm09 than the latter. Overall, fewer influenza detections were reported in countries with SARI surveillance, which can be explained by low influenza activity in most of these countries up to week 06/2014. Further, the participating countries use different surveillance systems and this may lead to differences in influenza (sub)type detections.

    For more information on surveillance of confirmed hospitalized influenza, please see ECDC?s Weekly Influenza Surveillance Overview (WISO) at European Centre for Disease Prevention and Control web site.

    Respiratory syncytial virus (RSV)

    Based on the data presented by countries reporting on RSV, the positivity rate had been gradually increasing since week 40/2013, peaked in week 50/2013 and has decreased in all the reporting countries since. This represents a slightly later start than in the previous season (see Country data and graphs for individual country data).

    EuroMOMO (European Mortality Monitoring Project)

    EuroMOMO is a project set up to develop and operate a routine public health mortality monitoring system to detect and measure, on a real-time basis, excess deaths related to influenza and other possible public health threats across 20 European Union (EU) countries.

    Pooled analysis of week data for 08/2014 showed that all-cause mortality was within the normal range for all reporting countries. Results of pooled analysis may vary, depending on which countries are included in the weekly analysis.

    For more information about the EUROMOMO mortality monitoring system please click here.


    Country comments (where available)

    Republic of Moldova: 33 samples were tested for Influenza A and B: 17 - were positive for RNA Influenza virus A(H3N2), 1 -positive for RNA A(H3N2)+RNA hRSV, 1 -positive for DNA Adenovirus, and 3 - for RNA hRSV.