Impact of the sequential IPV/OPV schedule on vaccination coverage levels--United States, 1997.

In January 1997, the Advisory Committee on Immunization Practices (ACIP) recommended adoption of a sequential inactivated poliovirus vaccine (IPV)-oral poliovirus vaccine (OPV) vaccination schedule. The schedule of injections of IPV at 2 months and 4 months of age, followed by OPV at 12-18 months and again at 4-6 years was intended to minimize the risk for vaccine-associated paralytic poliomyelitis (VAPP) while maintaining population immunity to the potential introduction of wild-type poliovirus. To determine whether this change may result in reduced or delayed vaccination coverage because parents or physicians might be reluctant to administer multiple injections at a single visit, CDC investigated the impact of the change to a sequential IPV-OPV vaccination schedule at two large West coast health maintenance organizations (HMOs). This report summarizes the results of the investigation and indicates that changing to an initial two doses of IPV was not associated with decreases in vaccination coverage levels of routinely recommended vaccinations.