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JAMA Patient Page
October 13, 2004


JAMA. 2004;292(14):1780. doi:10.1001/jama.292.14.1780

Poliomyelitis (polio) is a highly infectious viral disease that can involve the nervous system and can cause paralysis. Polio is most common in infants and children but can occur in adults. Because of widespread polio vaccination, the disease is now very rare in developed countries but still occurs in developing countries where vaccination coverage is not complete. The October 13, 2004, issue of JAMA includes an article about changing recommendations for giving the polio vaccine in the United States.


  • The poliovirus usually enters the body through the mouth from hands that have contacted the virus from an infected person.

  • The virus can be found in the throat and multiplies in the intestines.

  • The poliovirus can invade nerve cells that control muscles, including those involved with breathing.


  • Most people infected with the poliovirus have few, if any, symptoms.

  • Others have short-term symptoms that include headache, tiredness, fever, stiff neck and back, and muscle pain.

  • If the nervous system becomes infected, permanent paralysis can occur, usually of the legs and less commonly involving the breathing muscles, which may require artificial ventilation.

Preventing polio

Although there is no cure for polio, it can be prevented by giving the polio vaccine multiple times, ideally during childhood. There are 2 types of polio vaccine:

  • Oral polio vaccine (OPV) is taken by mouth and contains weakened but live polio virus.

  • Inactivated polio vaccine (IPV) contains killed poliovirus and is given as an injection.

Oral polio vaccine can rarely cause polio and is no longer available in the United States. Inactivated polio vaccine is thought not to be as good as OPV in preventing the spread of polio in a community. However, a person cannot get polio from IPV.

Before polio vaccine became available in the 1950s, thousands of cases occurred every year in the United States. The last case of polio originating in the United States (except for cases caused by OPV) was in 1979. To eliminate cases of polio acquired through OPV, the US national vaccination recommendations changed in 2000 to use exclusively IPV for vaccination against polio.

Polio in developing countries

In 1988, a global initiative was launched to eradicate polio. Since the initiative was launched, the number of polio cases has dropped by more than 99%, from an estimated 350 000 cases worldwide in 1988 to 1919 cases in 2002. In the same period, the number of countries with significant numbers of polio cases dropped from 125 to 7. Countries that presently have the highest rates of polio include Afghanistan, Egypt, India, Niger, Nigeria, and Pakistan.

For more information

Inform yourself

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Sources: American Academy of Pediatrics, Centers for Disease Control and Prevention, World Health Organization, National Institutes of Health.

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