Circulating influenza virus strains relative to trivalent inactivated vaccine strain in Thailand including the study period.

V = Influenza B Victoria linage; Y = Influenza B Yamagata lineage. Table adapted from Influenza viruses in Thailand: 7 years of sentinel surveillance data, 2004–2010, Chittaganpitch et al. Influenza and Other Respiratory Viruses DOI:10.1111/j.1750-2659.2011.00302.x.(years 2009–2010) and updated with data from http://www.thainihnic.org/influenza/main.php?option=newsletter (years 2011 to 2013). Note: Northern Hemisphere vaccine strains did not differ from southern vaccine strains after the inclusion of A/California/7/2009(H1N1) in April 2010. Circulating influenza virus strains relative to trivalent inactivated vaccine strain in Thailand including the study period.