The committee analyses data that encompass the epidemiological, antigenic and genetic characteristics of the most recently circulating influenza viruses as well as preliminary vaccine effectiveness data where they are available. In addition, panels of antisera from individuals (children, adults and elderly) who received seasonal trivalent inactivated vaccines are

tested to measure levels of antibodies to currently circulating influenza viruses. The committee assesses which viruses are likely to predominate in the forthcoming season and recommends vaccine candidates accordingly. With the WHO recommendations in mind, national and international regulatory agencies should determine which influenza viruses are best suited for influenza

vaccines to be licensed find more in their country. In the present report we describe the basis for the selection of candidate vaccine viruses recommended by the WHO in the 2013–2014 Northern Hemisphere influenza season. This report describes only those data that were available at the time of the WHO VCM held from February 18–20, 2013, in Geneva, Switzerland. The recommended viruses in the 2013–2014 Northern Hemisphere influenza season were: – an A/California/7/2009 (H1N1)pdm09-like virus. Influenza activity between the previous WHO VCM for seasonal influenza in September this website 2012 [1] and the VCM in February 2013 was reported by NICs and collated oxyclozanide in the WHO FluNet database (see http://www.who.int/flunet). During

this period, influenza activity was reported worldwide. Influenza activity in countries in the Northern Hemisphere was low in September and October but increased activity was reported in North America in November, in Europe from December onwards and in a number of countries in Asia in December or January. In the Southern Hemisphere, influenza activity generally declined from September onwards while in tropical areas many countries reported outbreaks of varying intensity. Regional A(H1N1)pdm09 activity was reported by a few countries in Asia, Central and South America as well as central Africa. In January, many countries in northern, eastern and central Europe and northern Africa (Algeria) had regional and widespread outbreaks. Localised and sporadic activity was also reported in many other countries in northern Africa, Asia and North America. Influenza A(H3N2) virus activity increased in November and caused widespread outbreaks in Canada and the United States of America where it was the predominant circulating virus subtype.