In the United States, APVs were first licensed in 1992 for the fourth and fifth booster doses in children 15 months to 6 years of age. In Canada, between March and July 1996, three APVs were licensed to be used as booster doses in children from 15 months to 6 years of age. At the recent National Immunization Conference, Connaught Laboratories Ltd., SmithKline Beecham Pharma Inc., Wyeth-Ayerst Canada Inc., and North American Vaccine Inc. indicated that they have applied for licensing of other combination products or intend to do so. Licensing of more combination products is expected in the foreseeable future. Generally, reactogenicity is less than that reported following the use of the whole-cell pertussis vaccine.
Immunogenicity compares favourably with whole-cell vaccines tested.
Efficacy of these products as fourth and fifth doses, especially in regard to the whole-cell vaccines used for the primary series in Canada, is not known. Licences were subsequently granted in several European countries for primary immunizations. As new data become available and additional licenses are granted in Canada, NACI will be recommending expanded indications. The present use of these products requires multiple injections for simultaneous administration of IPV, Hib, and hepatitis B vaccines. Data on the safety and immunogenicity of combined injections are not available as yet.