The best of EcoWatch, right in your inbox. Sign up for our email newsletter!
By Vanessa Schipani, FactCheck.org
Q: Did people develop cancer because of the polio vaccine?
A: There are no known cases, and it's very unlikely. In the 1950s and 1960s, people did receive polio vaccines contaminated with a virus that causes cancer in rodents. But research suggests this virus doesn't cause cancer in humans.