Genetic diversity of influenza A(H1N1)2009 virus circulating during the season 2010-2011 in Spain

Co-circulation of six different genetic groups of influenza A(H1N1)2009 viruses was identified in Spain during the season 2010-2011. Nevertheless, at this stage, none of the groups identified to date have resulted in significant antigenic changes according to data collected by World Health Organization Collaborating Centres for influenza surveillance.