Update on childhood immunization

Abstract

Changes made in 1997 and 1998 in the U.S. childhood immunization schedule are discussed, with a focus on the use of poliovirus, pertussis, and combination vaccines. Oral poliovirus vaccine (OPV), the vaccine of choice for all four closes in the polio immunization series since 1962, can cause vaccine-associated paralytic poliomyelitis (VAPP). The inactivated poliovirus vaccine (IPV) has not been associated with VAPP but must be administered by injection and provides inferior intestinal immunity. With the reduced threat of poliovirus importation into the United States, the risk of VAPP, although low, has become less acceptable. The Centers for Disease Control and Prevention accordingly recommended shift from OPV to IPV in the childhood immunization schedule for the United, States, effective January 1997. A sequential OPV anti IPV series is recommended, but the schedule includes an OPV-only option, which may be preferred in order to avoid the required injections, anti an IPV-only option, which is recommended for immunocompromised persons and their contacts. Concern over local and systemic reactions associated with whole-cell pertussis vaccines, in addition to controversy over a possible relationship between the whole-cell vaccine and neurologic damage, has led to the development of new diphtheria and tetanus toxoids and acellular pertussis vaccine products for use in life diphtheria and tetanus toxoids and pertussis immunization series. Several combination products were licensed in 1997, and more are on tire way. This will mean fewer inoculations for children. Increased use of IPV and acellular pertussis products could reduce tire frequency of VAPP due to OPV and the local and systemic reactions associated with whole-cell pertussis vaccine.