Adaptation of pandemic H2N2 influenza A viruses in humans.

Joseph U, Linster M, Suzuki Y, Kraus S, Rebecca H, Vijaykrishna D, Bestebroer T, Maurer-Stroh S, Webby R, Wentworth D, Fouchier RA, Bahl J, Smith GJD, members of the CEIRS H2N2 Working Group. 2015. J Virol 89: 2442-2447.


The 1957 A/H2N2 influenza virus caused an estimated 2 million fatalities during the pandemic. Since viruses of the H2 subtype continue to infect avian species and pigs, the threat of reintroduction into humans remains. To determine factors involved in the zoonotic origin of the 1957 pandemic we performed analyses on genetic sequences of 175 newly sequenced human and avian H2N2 virus isolates and all publicly available influenza virus genomes.