Medicine
The Development of Vaccines Through Antigenic Shift and Drift
Quick fact
The 2009 H1N1 'swine flu' pandemic was caused by antigenic shift, where a new virus emerged from a combination of pig, bird, and human influenza genes—a virus so new that almost no one had immunity.
Why this is interesting
Every year you need a new flu shot. But why can't you just get one vaccine and be protected for life? The answer lies in a genetic game of hide-and-seek played by the influenza virus.