This tragic disease killed at least 20 million people 100 years ago — and we’re still at risk

It's estimated that Influenza — the common flu — was the cause of death in 30 to 50 million people in 1918 and 1919. It was the second deadliest pandemic in history, just behind the Black Plague.

We brought in Dr. Stephen Morse, Professor of Epidemiology at Columbia University, to talk about how it happened — and why we're all still at risk. 

Follow TI: On Facebook

Join the conversation about this story »