What Is Polio?

Polio was once one of the most feared diseases in the U.S., but the creation of a vaccine in the 1950s ended the threat. The U.S. is now polio-free, though travelers can still bring it into this country.

Polio is short for "poliomyelitis." It's a virus that spreads easily between people who aren't vaccinated. In its most severe form, it can attack your spinal cord and brain and cause paralysis.

People of any age can get polio, but kids under 5 have the highest risk of getting it.

What Are the Symptoms?

Most people who catch the poliovirus don't have symptoms. About 1 in 4 people will have symptoms that look a lot like the flu, such as:

"Nonparalytic polio" symptoms like these often don't cause you to become paralyzed. They usually go away on their own within 10 days.

A smaller number of people have a more severe kind of polio that's called "paralytic polio." If you have it, your symptoms will start off like the mild ones above. Within a week, you'll also start to have:

  • A loss of reflexes
  • Severe muscle pain or weakness
  • Floppy limbs
  • A feeling of pins and needles in your legs
  • Paralyzed arms, legs, or both
  • Meningitis (an infection in your brain, spinal cord, or both)

Polio can be life threatening if the muscles you use to breathe get so weak that they no longer work.

Years after you have polio, you may start to have other symptoms. Known as "post-polio syndrome," you could have:

Polio is different from acute flaccid myelitis (AFM), a rare but serious condition that also attacks the nervous system and causes your muscles to weaken. Some people call AFM a "polio-like" illness, but it is not the same virus.

Is There a Cure?

There's no cure for polio, but a vaccine allows your body to fight off the virus.


Before the vaccine became available in the 1950s, the virus paralyzed thousands of people each year. By the 1970s, because many people had the vaccine, there were fewer than 10 cases of polio in the U.S.

Today, kids in the U.S. often get four doses of the inactivated poliovirus (IPV) vaccine, one dose each at ages:

  • 2 months
  • 4 months
  • Between 6 and 18 months
  • Between 4 and 6 years

If you're an adult got the polio vaccine as a child, you should still be immune. The only reason you might need a booster shot is if you plan to travel to a country where polio is still common or you spend time with someone who has polio.

If you didn't have all your vaccines or are unsure, your doctor can give them to you. You'll get 2 shots that are 4 to 8 weeks apart, and then a third shot 6 months to a year later.

While most of the world is also polio-free, three countries -- Afghanistan, Nigeria, and Pakistan -- have not fully stopped outbreaks of the virus.

What's the Treatment?

If you have polio, your doctor will focus on making sure that you're comfortable and try to prevent any other health issues. Some treatments include:

  • Pain relievers (like ibuprofen)
  • A ventilator (a device that helps you breathe)
  • Physical therapy that can help keep your muscles working
WebMD Medical Reference Reviewed by Dan Brennan, MD on October 13, 2019



CDC: "What is Polio?" "Polio Vaccination," Polio Elimination in the U.S." "About Acute Flaccid Myelitis," "Causes and Prevention of AFM," "Global Health: Our Progress Against Polio."

Mayo Clinic: "Polio."

Cleveland Clinic: "Polio."

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