The polio vaccine protects against polio, which is a very contagious viral infection that affects the spinal cord and brain. Polio can cause permanent muscle weakness, paralysis, and sometimes death.
Extensive vaccination has almost eradicated polio worldwide, but cases of wild-type polio still occur.
(See also Overview of Immunization.)
Vaccine Type
Worldwide, 2 formulations of polio vaccine are available:
Inactivated polio vaccine
Oral polio vaccine
Inactivated polio vaccine contains a piece of the poliovirus that does not cause infection. Because this piece of the virus is harmless, it cannot cause polio, but it does trigger a strong response from a person's immune system (see Active immunization).
Inactivated polio vaccine is the only polio vaccine that has been given in the United States since 2000.
The inactivated polio vaccine may be combined with other vaccines, such as the diphtheria, tetanus, and pertussis (DTaP) vaccine, hepatitis B vaccine, or Haemophilus influenzae type b vaccine.
Oral polio vaccine is a live, attenuated vaccine, which means it contains a weakened (attenuated) but still live version of the poliovirus. It is taken by mouth.
Very rarely (about 1 in 2.9 million doses), the live poliovirus in the oral vaccine mutates. The mutated vaccine virus can spread from the person who received the vaccine to unvaccinated people, continuing to mutate and potentially causing polio. In some countries, the mutated vaccine virus from the oral vaccine was virtually the only cause of polio, so most of these countries (including the United States) stopped using the oral polio vaccine. However, it is the preferred vaccine in many resource-limited areas in the world because the benefits of receiving it may outweigh the risks of not receiving it.
Dose of and Recommendations for Polio Vaccine
Inactivated polio vaccine is injected into a muscle or under the skin.
People who should get this vaccine
Inactivated polio vaccine is a routine childhood vaccination in the United States. Four doses are given: 1 at age 2 months, 1 at 4 months, 1 at 6 to 18 months, and 1 at 4 to 6 years. (See CDC: Recommended Immunizations for Birth Through 6 Years Old, United States, 2025.)
Polio is extremely rare in the United States. The risk of exposure may be increased if people travel to an area where polio is common (see CDC: Travelers' Health), work in a laboratory with materials that may contain the virus, or provide medical care to people who have polio.
If adults are unvaccinated or incompletely vaccinated, they should receive 3 doses of inactivated polio vaccine. Most adults who were born and raised in the United States after 1955 can assume they were vaccinated against polio as children unless there are specific reasons to believe they were not vaccinated.
Adults who completed their polio vaccination but who are at increased risk of exposure to poliovirus may receive 1 booster dose of vaccine.
In the United States, a case of vaccine-derived polio was identified in an unvaccinated person who acquired it in New York State in July 2022. No additional cases have been identified in the United States, but wastewater surveillance had detected the virus in samples across several New York counties, indicating local transmission (see also New York State Department of Health: Wastewater Surveillance). New York residents in areas with repeated poliovirus detection may be at higher risk of infection and should follow updated vaccination recommendations from the New York State Department of Health (see New York State Department of Health: Polio Vaccine).
People who should not get this vaccine
People who have had a serious, life-threatening allergic reaction (such as an anaphylactic reaction) after a previous dose of the vaccine or anaphylaxis to an component in the vaccine (such as the antibiotics streptomycin, neomycin, and polymyxin B) should not receive the vaccine.
Pregnant people who are not at increased risk of polio should not be given the polio vaccine even though there is no evidence that the vaccine harms pregnant people or their fetus. However, if a pregnant person is at increased risk of exposure to poliovirus and requires immediate protection, inactivated poliovirus vaccine can be given.
If people have a temporary illness, doctors usually wait to give the vaccine until the illness resolves (see also CDC: Who Should NOT Get Vaccinated With These Vaccines?).
Side Effects of Polio Vaccine
Common side effects include tenderness, redness, swelling, and skin thickening at the injection site. Fever, irritability, and tiredness may also occur but are typically mild and temporary.
Serious side effects are rare.
For more information about side effects, see the package inserts.
More Information
The following English-language resources may be useful. Please note that The Manual is not responsible for the content of these resources.
Centers for Disease Control and Prevention (CDC): Polio vaccine information statement
European Centre for Disease Prevention and Control (ECDC): Poliomyelitis: Recommended vaccinations