How can polio be prevented?

Two types of polio vaccine are available: oral polio vaccine (OPV) and inactivated polio vaccine (IPV).

OPV is made with a live but weakened virus. OPV protects vaccinated persons directly. OPV also protects other susceptible persons who are indirectly "vaccinated" as the vaccine virus spreads in the community. Because of wide use of OPV, no cases of paralytic polio caused by naturally circulating polio virus have been reported in the United States since 1979.

IPV is given by injection. It protects vaccinated persons as well as OPV, but it is not believed to be as effective as OPV in preventing the spread of polio virus among non-vaccinated persons. However, IPV is not known to cause polio disease.

As of January 1997, the recommended schedule for polio vaccination for children was two doses of IPV at 2 and 4 months of age, followed by two doses of OPV at 12-18 months and 4-6 years. This schedule is expected to reduce the small number of polio cases caused by the oral vaccine.

Schedules containing all OPV or all IPV can still be used, too. IPV can be given at 2, 4, and 12-18 months, and 4-6 years. OPV can be given at 2, 4, and 6-18 months, and 4-6 years. Parents and doctors can choose among the three schedules.

Booster doses of polio vaccine are also recommended for persons traveling to areas of the world where polio is still a problem.

As is the case with all immunizations, there are important exceptions and special circumstances. Health-care providers should have the most current information on recommendations about polio vaccination.