Start of the 2014/15 influenza season in Europe: drifted influenza A(H3N2) viruses circulate as dominant subtype.


Start of the 2014/15 influenza season in Europe: drifted influenza A(H3N2) viruses circulate as dominant subtype The influenza season 2014/15 started in Europe in week 50 2014 with influenza A(H3N2) viruses predominating. The majority of the A(H3N2) viruses character-ised antigenically and/or genetically differ from the northern hemisphere vaccine component which may result in reduced vaccine effectiveness for the season. We therefore anticipate that this season may be more severe than the 2013/14 season. Treating influenza with antivirals in addition to prevention with vaccination will be important. Influenza activity started increasing in the western part of the World Health Organization (WHO) European Region during week 50 2014, when Malta, the Netherlands and Sweden reported medium intensity of influenza activity which refers to usual activity of influenza season [1]. Rates of influenza-like illness (ILI) and/or acute respiratory infection (ARI) have continued to increase, and in week 2 2015, 13 countries (UK)) in the WHO European Region reported medium intensity and Albania, the Netherlands, Portugal, Spain and Switzerland had ILI rates above the epidemic threshold for the pre-season [2]. Of the 13 countries reporting medium intensity, six (Finland, the Netherlands, Portugal, Slovenia, Sweden and the UK (England)) reported patterns of widespread activity with laboratory confirmed influenza cases in 50% or more of their administrative units (or reporting sites). Since October 2014, all 53 Member States of the WHO European Region report their epidemiological and viro-logical influenza surveillance data to The European Surveillance System (TESSy), hosted by the European Centre for Disease Prevention and Control (ECDC) [1]. The data are jointly published with the WHO European Regional Office to describe the annual occurrence of influenza (timing and spread), its impact and severity (groups which are most affected), the predominating influenza type and subtype, as well as analyses of virus strains to support the WHO recommendations for the composition of seasonal influenza vaccines (www. The northern hemisphere influenza vaccine composition recommendation is given by WHO at the end of February each year. Influenza surveillance in Europe is mainly based on primary care sentinel sites collecting specimens from patients with ILI and/or ARI [1,3]. Data are collected at the national level and reported to the European level according to standardised case definitions [4,5]. The national influenza centres perform antigenic and genetic characterisation of influenza viruses as well as antiviral susceptibility testing of a representative sample of virus isolates. In addition to the primary care surveillance, …

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Influenza Update N° 228

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Influenza case definitions. Stockholm: ECDC. [Accessed 22 Available from: Available from

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Rapid risk assessment: circulation of drifted influenza A(H3N2) viruses in the EU/EEA

  • 2014
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