(Re)emergence of A(H1N1)pdm09 influenza viruses with pandemic markers in the 2018/2019 flu season in the USA

During the 2009 pandemic, the Centers for Disease and Control and Prevention (CDC) estimated that 43 to 89 million cases of swine flu were reported during a 1-year span, with 1799 deaths in 178 countries worldwide. Now, nine years later, A(H1N1)pdm09 influenza viruses, which caused this pandemic, have reemerged and become the dominant subtype for the current  2018/19 flu season in the USA. The in silico analysis of A(H1N1)pdm09 viruses isolated in USA in October and November 2018, performed using the electronic biology platform “wEB”, showed that these viruses carry previously identified pandemic markers suggesting their increased pandemic potential. Possible consequences of these findings are discussed.