Poliomyelitis

Poliomyelitis, more commonly known as polio, is a disorder caused by a virus and marked by potentially paralyzing nerve-related damage, which can be fatal. Fifty years ago it was a major killer of children, and it remains a threat in parts of Asia and Africa today. Vaccination programs eliminated the disease in the Americas in 1994, with the last case of wild poliovirus in the US reported in 1979. As of 2004, polio has been eradicated in the Americas, the Western Pacific, and Europe.

Poliomyelitis is a communicable disease caused by viral infection and occurs through direct contact with infected secretions. Polio is found worldwide, but immunization has reduced the incidence. Clinical polio affects the central nervous system (brain and spinal cord). Disability is more common than death.

Vaccines for Poliovirus

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Two poliovirus vaccines have been available in the US: oral poliovirus vaccine (OPV), which is a live-virus vaccine, and inactivated poliovirus vaccine (IPV), which is a killed vaccine that is administered by injection. Both produce immunity in over 95% of people. The live-virus used in the vaccine, however, has, in some cases, reverted to a form that can cause polio in unvaccinated people. This is a particular danger in developing countries where vaccination rates are low. The Centers for Disease Control and Prevention now recommends only the inactivated IPV vaccine for children. The schedule is four doses of IPV at ages 2 months, 4 months, 6 to 18 months, and 4 to 6 years.