Although oseltamivir-resistant seasonal H1N1 influenza A viruses have been identified since 2007 (the H274Y mutation) [71] , in 2009 the CDC reported that most circulating strains of the novel H1N1 influenza A virus were sensitive to the NI, oseltamivir and zanamivir, but that nearly all strains were resistant to the amantadines [41••, 72] . Consequently, the ACIP has advised against the use of M2 inhibitors for treatment of influenza, except in selected circumstances [41••] .