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. 2018 Jul;10(Suppl 19):S2238–S2247. doi: 10.21037/jtd.2017.12.122

Figure 3.

Figure 3

Annual prevalence of influenza viruses, by subtypes, in the United States between 2009 and 2016. With the exception of 2009/2010 and 2010/2011 influenza season, a single subtype typically dominates during peak influenza activity period. During the 2009/2010 season, only A(H1N1)pdm09 circulated while in 2010/2011, both A(H1N1)pdm and H3N2 subtypes were detected at similar proportions. This suggests that co-infections with multiple influenza virus subtypes can occur at low frequencies. Data was retrieved from World Health Organization’s (WHO)’s Global Influenza Surveillance and Response System (GISRS) online reporting portal, FluNet (http://www.who.int/influenza/gisrs_laboratory/flunet/en/).