Influenza Vaccine — Outmaneuvering Antigenic Shift and Drift

Abstract

The winter of 2003–2004 will be remembered as a year in which stories about influenza dominated the news and patients young and old clamored for influenza vaccination. This intense interest is the result of the confluence of multiple circumstances. The onset of the annual influenza epidemic came earlier than expected and was accompanied by reports of severe disease in previously healthy children, associated with the isolation of antigenically variant influenzaviruses represented by the prototypic strain A/Fujian/411/2002 (H3N2). There was concern that the available influenza vaccine would not be optimally effective against this strain of virus, but at the same time, the unexpectedly high demand for vaccination led to shortages in many areas. Perhaps it should not come as a surprise that this infinitely adaptable pathogen has again found a way to thrust itself into our consciousness. How are these events linked, and how do they fit into our overall understanding of influenza?