Polio

What Is Polio?

Polio is caused by a virus that attacks the brain and spinal cord. It is very contagious. The virus spreads through contact with feces (poop) from an infected person or droplets from a sneeze or cough.

A Quick Guide to Polio

How it spreads	Poop, coughs, and sneezes
Common symptoms	Most people have no symptoms 1 out of 4 have flu-like symptoms, including sore throat, fever, tiredness, nausea, headache, stomach pain
Impact	1 out of 200 to 1 out of 2,000 have arms or legs left weak or paralyzed (can’t move) Paralysis can kill if breathing muscles are affected
Vaccine?	Yes (4 doses for children, 3 for unvaccinated adults)
Can it be cured?	No

How Common or Serious is Polio?

The United States has not had a major outbreak of polio for decades, thanks to widespread vaccination. However, the virus spread in New York in 2022 and paralyzed an unvaccinated person, showing that the threat is not gone.

Polio used to be a major problem in the US, paralyzing about 16,000 people each year until the first vaccine was introduced in the 1950s.

• Vaccination has eliminated polio from most of the world, but outbreaks still happen (primarily in countries without routine vaccination). Polio sometimes spreads beyond the countries where it still circulates.
• While polio is not common in the US anymore, travelers sometimes bring it back with them. The US Centers for Disease Control and Prevention’s Travel Notices lists polio as a Level 2 threat on its 4-point scale, advising people who are traveling to certain areas to check their vaccination status and get a booster if needed.
• Most people who are infected with the polio virus have no symptoms. For those who do develop symptoms, most are mild and they recover fully.
• In serious cases, people are left unable to move one or more arms or legs. If breathing muscles are affected, the infected person can die.

What Causes Polio?

Polio is caused by a virus that can spread in droplets when an infected person coughs or sneezes, but it mainly happens through contact with feces (poop) from an infected person. Some ways this can happen are:

• Drinking untreated water
• Eating raw or undercooked food that has come in contact with an infected person’s poop; for example, if the food preparer didn’t wash their hands after using the bathroom
• Touching a contaminated object, then putting your fingers in your mouth
• Children putting contaminated toys or other objects in their mouths

Infected people can spread the polio virus before they start to show symptoms and can continue to spread the virus for up to 2 weeks. People who don’t have symptoms can still spread the virus.

Who is Most at Risk for Polio?

• Young children in areas with circulating virus
• Travelers visiting affected areas

 Symptoms: What Does Polio Feel Like?

• Most people infected with the polio virus have no symptoms.
• About 1 in 4 infected people have mild, flu-like symptoms. These can include a fever, headache, sore throat, feeling very tired, feeling sick to your stomach, or having stomach pain. These symptoms usually go away on their own in a few days.
• Between 1 in 20 and 1 in 100 will develop swelling of the brain or spinal cord, which causes pain or stiffness in the neck, back, arms, or legs. This also usually goes away in a few days.
• In between 1 in 200 and 1 in 2,000 cases, the infected person’s arms, legs, or both are left weak or unable to move.
• Some people who recover from polio may develop post-polio syndrome. Symptoms of post-polio syndrome include muscle weakness, joint pain, and physical and mental tiredness, which develop long after polio illness has resolved. People can have post-polio syndrome as many as 15 to 40 years after getting infected. It may be minor or cause problems that interfere with daily life.

Prevention

The polio vaccine is the best way to prevent polio illness. There are a number of different types of polio vaccines used around the world.  The US only uses an inactivated (killed) polio vaccine given by injection.

Children should get 4 doses, at age:

• 2 months
• 4 months
• 6 to 18 months
• 4 to 6 years

Nearly all US adults have been vaccinated against polio. Adults who have not been vaccinated or are not sure of their status should get 3 doses:

• Second dose 1 to 2 months after the first
• Third dose 6 to 12 months after the second

Travelers visiting countries where the virus is circulating should get a polio booster vaccine, if they haven’t previously had one.

Washing your hands often with soap and water also will help keep the virus from spreading. (Most alcohol-based hand sanitizers will not kill the polio virus.)

Treatment

There is no treatment or cure for polio. Physical or occupational therapy can help with weakness in the arms or legs.

Reviewed and updated April 2026

Sources: American Academy of Family Physicians, American Academy of Pediatrics, Centers for Disease Control and Prevention