Polio (Poliomyelitis)

What is polio?

Polio is a highly infectious disease caused by the poliovirus. Most people infected with poliovirus have no symptoms. In some, polio can cause weakness and paralysis of the arms, legs, and breathing muscles and can result in permanent disability and even death. Polio primarily affects unvaccinated children, but anyone who is not fully vaccinated against the virus is at risk of developing severe illness if exposed.

In recent years, global vaccination efforts have significantly reduced the number of polio cases worldwide. Polio is still a concern in countries that do not have access to the vaccine.

What are the symptoms of polio?

Many people infected with the polio virus do not develop symptoms. Some people will have flu-like symptoms that include:

  • Fever
  • Tiredness
  • Nausea
  • Headache
  • Sore throat
    • Stomach pain

A smaller amount of infected people develop serious symptoms that affect the brain and spinal cord. These symptoms include:

  • Infection of the covering of the spinal cord or brain (meningitis).
  • Paralysis or weakness of the arms and legs

In some cases, polio can lead to permanent paralysis and disability. Limb paralysis can improve over time. In some people, new muscle pain and weakness may develop 15 to 40 years later. This is called “post-polio syndrome.”

How does polio spread?

Polio is found in the stool and saliva of people who are infected. Polio spreads easily when a person puts something in their mouth that has infected feces or saliva on or in it or has close contact with someone who is infected. It can also happen from eating or drinking contaminated food or water.

People can spread polio up to two weeks before they display symptoms, which is what makes polio difficult to stop in unvaccinated populations.
How can we prevent polio?

Vaccination is the best way to protect against polio. Children are vaccinated against polio as part of the routine childhood vaccine schedule. Learn more about the polio vaccination on the DOH vaccine webpage.

If you are traveling outside of the United States, make sure you are up to date on your vaccinations.

In addition to vaccination, it is always important to have good hygiene practices. Alcohol-based sanitizers do not kill poliovirus, so wash your hands often with soap and water. Avoid touching surfaces or objects and then touching your mouth or eyes.

Polio is a notifiable condition. For more information on identifying and reporting poliovirus, visit the Polio Notifiable Conditions web page.

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