Genetic characterization of influenza viruses from influenza-related hospital admissions in the St. Petersburg and Valencia sites of the Global Influenza Hospital Surveillance Network during the 2013/14 influenza season

Abstract Background Continuous surveillance for genetic changes in circulating influenza viruses is needed to guide influenza prevention and control. Objectives To compare intra-seasonal influenza genetic diversity of hemagglutinin in influenza A strains isolated from influenza hospital admissions collected at two distinct sites during the same season. Study design Comparative phylogenetic analysis of full-length hemagglutinin genes from 77 isolated influenza A viruses from the St. Petersburg, Russian Federation and Valencia, Spain sites of the Global Influenza Hospital Surveillance Network (GIHSN) during the 2013/14 season. Results We found significant variability in A(H3N2) and A(H1N1)pdm…