Handbook on the Late Effects of Poliomyelitis for Physicians and Survivors©
The two types of trivalent polio vaccines currently available are the inactivated poliovirus vaccine (IPV) developed by Jonas E. Salk (1955) and administered by injection, and the oral poliovirus vaccine (OPV) developed by Albert B. Sabin and approved for use in 1962.
The World Health Organization (WHO) recommends the use of the OPV in its mass campaign to eradicate the wild poliovirus from the world by the year 2000. The OPV is easier to administer to large populations of infants and children and is less costly than the IPV injection. The OPV stimulates immunity in the intestines, a site where the virus multiplies, and reduces the risk of spread to other children.
Since the OPV is a "live" vaccine, there is a risk that one dose in 2.4 million will cause polio, or one in 750,000 individuals receiving their first dose will contract poliomyelitis (Centers for Disease Control and Prevention, 1997). Acute poliomyelitis also has been reported in non-immunized persons who came into contact with the poliovirus shed by an infant or child recently vaccinated with OPV, most often from changing diapers. OPV should not be used to immunize individuals with a compromised immune system, their household contacts, or nursing personnel in close contact. OPV should not be given to anyone who is pregnant or over 18 years of age, since they are reported to be more susceptible to vaccine-induced poliomyelitis.
The Centers for Disease Control and Prevention (CDC) recommends that travelers to countries where polio is epidemic or endemic receive the IPV before departure. For an up-to-date listing of the countries in question, call the CDC's automated vaccine information line at 888-232-3228 or the autofax line at 888-232-3299 or log on to www.cdc.gov and choose "Traveler's Health."
In the United States, the current (1999) immunization schedule against poliomyelitis approved by the Advisory Committee on Immunization Practices (ACIP), with the support of the American Academy of Pediatrics and the American Academy of Family Physicians, recommends that the first two doses of poliovirus vaccine be IPV administered at ages 2 and 4 months, followed by two doses of OPV at 12-18 months and 4-6 years. Use of IPV for all doses also is acceptable and is recommended for immunocompromised persons and their household contacts. OPV is no longer recommended for the first two doses of the schedule and is accept-able only for special circumstances, such as children of parents who do not accept the recommended number of injections, late initiation of immunization which would require an unacceptable number of injections, and imminent travel to polio-endemic areas. In June 1999, the ACIP recommended an IPV-only immunization schedule. The CDC must approve the recommendation before it takes effect January 1, 2000.