A group of children in Pittsburgh received the polio vaccine developed by Jonas Salk on this day in 1954. The field trials remain one of the largest clinical trials ever held, with around 624,000 children receiving either the placebo or vaccine. A year later, the world found out that the vaccine had an 80-90 percent efficacy rate.
Before the vaccine was introduced, half a million people were killed or paralyzed by polio every year. It was a massive step forward in the fight against a disease that had plagued humanity for thousands of years.
By 1957, annual U.S. polio cases had dropped from 58,000 to less than a tenth of that number. In 1961, just 161 cases were reported. Today, polio has been virtually eradicated, though some cases still occur in destitute communities.
You can read more about the early history of polio immunizations in this article from the World Health Organization.
