Multiple Infections with Seasonal Influenza A Virus Induce Cross‐Protective Immunity against A(H1N1) Pandemic Influenza Virus in a Ferret Model

Abstract

These data suggest the reduced incidence and severity of infection with A(H1N1)pdm virus in the adult population during the 2009-2010 influenza season may be a result of previous exposure to seasonal influenza A viruses.