Poliomyelitis (often shortened to polio) is a serious viral disease that attacks the nervous system and can cause paralysis, meaning it can make parts of your body unable to move. Before vaccines were developed in the 1950s, polio terrified parents everywhere because it struck suddenly, often during summer, and could leave previously healthy children unable to walk, or even unable to breathe on their own.

The disease spreads through contaminated water or food, and most people who catch it have mild symptoms like a fever or sore throat. But in some cases, the virus attacks nerve cells in the spinal cord that control muscles. When this happens, a person might lose the ability to move their legs, arms, or other body parts. The most severe cases affected breathing muscles, and patients needed to use iron lungs, large machines that helped them breathe by creating pressure around their bodies.

Dr. Jonas Salk developed the first successful polio vaccine in 1955, followed by Dr. Albert Sabin's oral vaccine. These vaccines became one of medicine's greatest triumphs. Thanks to worldwide vaccination efforts, polio has been eliminated from most countries. In the United States, the last naturally occurring case occurred in 1979. Today, health workers continue vaccinating children around the world, working to eradicate polio completely, just as smallpox was eliminated in 1980.