Poliovirus vaccine options.

As a result of the success of immunization, indigenous wild poliomyelitis has disappeared from the United States. Of 142 confirmed cases of paralytic poliomyelitis reported in the United States from 1980 to 1996, 134 were classified as vaccine-associated paralytic poliomyelitis (VAPP). Persons with VAPP have a disabling illness, and this has caught the attention of the lay media. The risk of VAPP is one case per 750,000 doses distributed for the first dose of oral poliovirus vaccine (OPV) and one case per 2.4 million doses of OPV distributed overall. Because of this risk, most parents prefer a vaccine schedule that starts with inactivated poliovirus vaccine (IPV), even though extra injections are required. IPV does not cause VAPP. New studies show that high immunization rates can be achieved in disadvantaged populations with a schedule starting with IPV. The American Academy of Family Physicians now recommends that the first two doses of poliovirus vaccine should be IPV; that is, either an all-IPV schedule or a sequential schedule of two doses of IPV followed by two doses of OPV. OPV is no longer recommended for the first two doses and is acceptable only under special circumstances, such as when parents do not accept the recommended number of injections.