TY - JOUR T1 - Improving influenza virological surveillance in Europe: strain-based reporting of antigenic and genetic characterisation data, 11 European countries, influenza season 2013/14 JF - Euro.Surveill Y1 - 2016 A1 - Broberg,E. A1 - Hungnes,O. A1 - Schweiger,B. A1 - Prosenc,K. A1 - Daniels,R. A1 - Guiomar,R. A1 - Ikonen,N. A1 - Kossyvakis,A. A1 - Pozo,F. A1 - Puzelli,S. A1 - Isabelle Thomas A1 - Waters,A. A1 - Wiman,A. A1 - Meijer,A. KW - a KW - age KW - AGE GROUP KW - AGE GROUPS KW - Age-group KW - ALL KW - Area KW - article KW - Case KW - composition KW - Control KW - Countries KW - data KW - Decision KW - Decision Making KW - disease KW - ecdc KW - ECONOMIC KW - electronic KW - Europe KW - European KW - European countries KW - Genetic KW - Group KW - INFLUENZA KW - IS KW - journal KW - LEVEL KW - levels KW - mechanism KW - p KW - Patient KW - patients KW - pilot KW - pilot study KW - prevention KW - proportion KW - SELECTED KW - study KW - Surveillance KW - Sweden KW - System KW - vaccine KW - VIRUS KW - Viruses AB - Influenza antigenic and genetic characterisation data are crucial for influenza vaccine composition decision making. Previously, aggregate data were reported to the European Centre for Disease Prevention and Control by European Union/European Economic Area (EU/EEA) countries. A system for collecting case-specific influenza antigenic and genetic characterisation data was established for the 2013/14 influenza season. In a pilot study, 11 EU/EEA countries reported through the new mechanism. We demonstrated feasibility of reporting strain-based antigenic and genetic data and ca 10% of influenza virus-positive specimens were selected for further characterisation. Proportions of characterised virus (sub)types were similar to influenza virus circulation levels. The main genetic clades were represented by A/StPetersburg/27/2011(H1N1)pdm09 and A/Texas/50/2012(H3N2). A(H1N1)pdm09 viruses were more prevalent in age groups (by years) < 1 (65%; p = 0.0111), 20-39 (50%; p = 0.0046) and 40-64 (55%; p = 0.00001) while A(H3N2) viruses were most prevalent in those >/= 65 years (62%*; p = 0.0012). Hospitalised patients in the age groups 6-19 years (67%; p = 0.0494) and >/= 65 years (52%; p = 0.0005) were more frequently infected by A/Texas/50/2012 A(H3N2)-like viruses compared with hospitalised cases in other age groups. Strain-based reporting enabled deeper understanding of influenza virus circulation among hospitalised patients and substantially improved the reporting of virus characterisation data. Therefore, strain-based reporting of readily available data is recommended to all reporting countries within the EU/EEA VL - 21 CP - 41 U1 - 37172 M3 - http://dx.doi.org/10.2807/1560-7917.ES.2016.21.41.30370 ER -