The Question

What is the relationship between influenza vaccination and antigenic drift? Antigenic drift in influenza is the reassortment of virus gene segments, which will cause people who have had the illness in the past to lose their immunity to the new strain.

What we found

Antigenic drift can be statistically detected during some seasons. If antigenic drift occurs on the time scale of a single influenza season, it may be associated with the presence of herd immunity at the beginning of the season and may indicate a need to monitor for vaccine updates at the end of the season.

Why it matters

Improved detection of short-term antigenic drift would significantly benefit influenza monitoring efforts and vaccine selection.