Polio is a disease caused by a virus.
The polio virus lives in feces of infected people and spreads by direct contact with an infected person or contaminated food or water.
Polio in the U.S. has virtually vanished thanks to an aggressive vaccination program. However, polio is still a threat, as polio is still around in some countries.
Polio can paralyze breathing muscles, leading to death.
Polio can also permanently paralyze arms and legs.
Before there was a vaccine, polio killed and paralyzed tens of thousands of people in the U.S, and millions overseas each year.
All children should get three or four doses of polio vaccine (depending on brand of vaccine) starting at 2 months of age and a booster dose at 4-6 years old.