Poliomyelitis (polio)

Poliomyelitis is a highly contagious infection caused by poliovirus, which is transmitted from person to person through exposure to fecal material or respiratory secretions containing the virus. The incubation period ranges from nine to twelve days. Most poliovirus infections are asymptomatic. Initial symptoms, when they occur, are similar to those of other viral infections and may include fever, headache, muscle aches, malaise, nausea, vomiting, and sore throat. In roughly one in a thousand cases, poliovirus attacks the spinal cord or brainstem, leading to paralysis in various parts of the body, most often the legs.

There has been a recent resurgence of polio in west and central Africa, chiefly Nigeria, related in part to a temporary interruption of immunization programs by local authorities in that country. Cases have also been reported from Benin, Botswana, Burkina Faso, Cameroon, Central African Republic, Chad, Ghana, Guinea, Ivory Coast, Mali, Niger, Sudan, and Togo. Poliovirus continues to be transmitted in the Indian subcontinent and in certain countries in the Middle East, particularly Egypt and Afghanistan.

All children should receive four doses of inactivated polio vaccine at ages 2 months, 4 months, 6-18 months, and 4-6 years. An accelerated immunization schedule is recommended for children who have not completed their polio immunizations and who may be traveling to places where polio still occurs. Adults who will be traveling to an area where polio is reported and who have never been immunized or whose immunization status is unknown should be given a total of three doses of inactivated polio vaccine separated by at least 4 weeks from each other. Optimally, the third dose should not be given until at least 6 months after the second, but this is generally not feasible.

Any adult who completed the full childhood series of polio immunizations but never had a booster as an adult should receive a single dose of polio vaccine before travel to a polio-endemic area. The National Travel Health Network and Centre (U.K.) has recently stated that, if more than 10 years have elapsed since the last dose of polio vaccine, the traveler should be reimmunized. However, the U.S. Centers for Disease Control and Health Canada continue to advise that a single booster during adulthood is sufficient and that there is no evidence that additional doses are necessary. In the United Kingdom, inactivated polio vaccine is available in combination with tetanus and diphtheria vaccine (Revaxis), to facilitate adult reimmunization.

Inactivated polio vaccine may cause mild pain or redness at the site of injection. Serious side-effects have never been documented. Since inactivated polio vaccine includes trace amounts of streptomycin, neomycin and polymyxin B, individuals allergic to these antibiotics should not receive the vaccine. Mild illness, including mild diarrhea, is not a contraindication to vaccination.

Inactivated polio vaccine has essentially replaced oral polio vaccine in the United States, the United Kingdom, and Canada, because the latter may cause paralytic poliomyelitis, though this is rare. Oral polio vaccine is recommended only for unvaccinated children who will be traveling in less than four weeks to an area where polio is endemic and for mass vaccination campaigns to control polio outbreaks.

Polio has been eradicated in the Americas, in Europe, and in the Western Pacific region, which includes large parts of Southeast Asia as well as the Pacific Islands. Travelers to these countries do not require polio boosters.

From the World Health Organization (WHO)

Poliomyelitis fact sheet

Poliomyelitis vaccine

Safety of polio vaccines

From the Centers for Disease Control (CDC)

Poliomyelitis

Poliomyelitis Prevention in the United States: Updated Recommendations of the Advisory Committee on Immunization Practices (ACIP) (primarily for physicians)

From the National Travel Health Network and Centre (U.K.)

Poliomyelitis