New A/H3N2 Influenza Variant: a Small Genetic Evolution but a Heavy Burden on the Italian Population during the 2004-2005 Season

Abstract

Recurrent epidemics of influenza are due to the continuous emergence of new antigenic variants. Antigenic drift, which occurs when the accumulation of point mutations results in amino acid changes in surface glycoproteins, is the mechanism used by influenza viruses to escape from immunological