Follow your curiosity

What discovery has been shared with you?

FACTREE gives you something interesting to discover every day — and something worth talking about together.

Start with one fact. Explore it, go deeper, then follow whichever branch catches your imagination.

Choose subjects for a surprise

Exploring any topic

Begin your discovery

Your next discovery is one click away.

Choose one or more subjects above, or leave Any Topic selected and let curiosity decide.

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.