Polio

What Is Polio?

Polio is a highly contagious infectious disease caused by a virus that invades the nervous system. Poliovirus spreads through contact with the stool (feces) of an infected person or droplets from a sneeze or cough.

Burden

In the 1950s, before polio vaccines were available in the US, polio outbreaks caused more than 15,000 cases of paralysis each year. After polio vaccines were introduced in the US, the number of polio cases fell rapidly to less than 100 per year in the 1960s and fewer than 10 in the 1970s. In 2022, a case of paralytic polio and detection of poliovirus in wastewater in New York underscored the importance of routine polio vaccination.

Symptoms

Most individuals infected with the virus will not experience any symptoms at all; some individuals will experience minor symptoms such as fever, fatigue, nausea, headache, flu-like symptoms, stiffness in the neck and back, and pain in the limbs which often resolves completely.

In some people, the poliovirus can result in paralysis (usually the legs), which can lead to permanent disability. The poliovirus can cause death when it paralyzes the muscles that help people breathe.

About 1-5 out of 100 people who are infected with poliovirus infection will develop meningitis (an infection of the spinal cord or brain).

Prevention

Since widespread use of the vaccine, which began in the 1950s, polio has been eliminated in the US. However, the virus continues to circulate in different parts of the world, which is why polio vaccination is recommended for all children.

Children should receive 4 doses total of polio vaccine, with 1 dose at each of the following ages:

2 months
4 months
6-18 months
4-6 years

Most US adults were vaccinated as children and do not need further vaccine doses. Adults age 18 years and older who are unvaccinated or unsure of their vaccination status should complete a primary polio vaccination series with inactivated polio vaccine (IPV) as soon as possible.

Fully vaccinated adults at increased risk for poliovirus exposure (e.g., those traveling to countries where there is an increased risk) may receive a single lifetime booster dose of IPV.