In the light of earlier, smaller test projects, the polio vaccine had seemed likely to be safe and highly effective.

North Carolina became the first state in the nation to require polio vaccines for all children.

Many said his polio vaccine, based on a killed virus, would never work.

It began as a research facility to create polio vaccine.

Avoid contact with people who have recently received oral polio vaccine.

The polio vaccine is given in a series of shots.

The polio vaccine is used to help prevent these diseases in children.

So I guess we shouldn't have developed the polio vaccine because it couldn't also cure cancer or the common cold.

The first live oral polio vaccine tested on a large population.

This discovery set the stage for the development of the polio vaccine.