Jonas Salk

Imagine a tiny shot that could stop a disease that once paralyzed thousands of children — that's the real story of Jonas Salk. Jonas Salk (1914–1995) was an American doctor and scientist in the mid-1900s. His most important work was creating the first safe, widely used polio vaccine, announced in 1955, which taught the body to fight the poliovirus without causing the illness.

In 1954 a massive field trial tested his vaccine on more than a million children across the United States. Salk used a killed (inactivated) form of the poliovirus so the vaccine could safely train the immune system. After the trial showed the vaccine worked, mass immunizations began and polio cases dropped dramatically. Salk also chose not to patent the vaccine so it could be made and shared widely.

Today, thanks largely to Salk’s work, polio is rare in most countries and millions of children have been spared paralysis. He later founded the Salk Institute in California to help other scientists pursue medical discoveries. His story shows how careful science, big tests, and putting people first can change the world. His work inspired later vaccine research and continues to protect children today.