Jonas Salk

While no one was safe from polio, the virus mostly affected kids. Most who were infected didn’t show any symptoms. But they were still highly contagious, or able to easily spread the disease. Other people experienced sore throats, pain, and stiffness.

For some who got sick, the effects were much worse. Polio attacked their muscles. Some kids couldn’t walk or even breathe without help from a machine.

One way the disease spread was through coughs. So sick kids quarantined, or stayed away from others, to help stop the virus’s spread.

Salk had been a doctor for years when polio struck the U.S. He had always wanted to make a difference. Now was his chance.

In 1947, he began to work on a polio vaccine, a shot containing harmless parts of the virus.

“A vaccine takes a part of the virus and shows it to your immune system,” explains Nicole Doria-Rose. She’s a scientist at the National Institutes of Health. “Your immune system is prepared to fight it off if you’re exposed to it.”

By 1954, Salk had created what he thought to be a successful polio vaccine. It was an amazing discovery. But before giving it to the public, Salk had to be sure it was safe. He tested it on his family and himself. Then it was tested on nearly 2 million kids.

Finally, on April 12, 1955, doctors made an important announcement. Salk’s polio vaccine had been proved to be safe and effective.

Salk’s discovery saved countless people from getting sick and dying. Americans no longer needed to live in fear of polio.

Doria-Rose says that Salk and scientists like him paved the way for many vaccines that followed. Today, those vaccines are being used to prevent Covid-19 and other dangerous diseases.

1. What were the symptoms of polio?

2. Why were kids with polio quarantined?

3. Why was April 12, 1955, an important day in America?