On this day, April 12, 1955, it was announced that the polio vaccine Jonas Salk developed was safe.

[patphil]

7. They brought the vaccine right into my school, and mass vaccinated the whole school.

I don't remember exactly when, but it was mid-50's. It was that dangerous a disease, and parents had not yet been programmed to reject science.
As a result of this early vaccine, and the ones that followed, polio was all but wiped out in the US, and most of the world. Before then, thousands of kids were killed, and 10's of thousands of young kids in the US were paralyzed each year.
In terms of numbers infected, and killed, Covid-19 is much worse, but still millions reject the vaccine.
Strange how people can be programmed to act against their own self interests, and also not to be concerned about the safety of others.