Jonas Salk developed a vaccine for polio in the 1950s.
Salk led a research team at the University of Pittsburgh that created an inactivated poliovirus vaccine, often called the Salk vaccine. Instead of using live virus, it used virus particles chemically killed so they could stimulate immunity without causing the disease. The approach was especially significant because polio could cause permanent paralysis or death, particularly in children.
A large field trial involving about 1.8 million children produced highly encouraging results. On April 12, 1955, the vaccine was declared safe and effective and was licensed for use in the United States. Mass vaccination soon sharply reduced polio cases.
The answer is sometimes confused with Albert Sabin, who later developed a live, weakened oral polio vaccine. Salk’s vaccine was injected, while Sabin’s became famous as oral drops. Both targeted poliomyelitis, but they were distinct vaccines developed by different scientists.