FAQs Influenza

Antigenic Drift and Antigenic Shift in Influenza Virus

Antigenic Drift and Antigenic Shift in Influenza Virus

Influenza virus has two ways to change — one slow and one fast. The slow change is known as drift and the fast change is called shift.

Why does influenza come back year after year?

Why does influenza come back year after year?

Influenza virus changes every time it reproduces, generating progeny that are ever so slightly different from the parent.