On Sept. 27, 1996, the Food and Drug Administration (FDA) licensed a Haemophilus b Conjugate Vaccine (ActHIB) combined by reconstitution with diphtheria and tetanus toxoids and acellular pertussis vaccine (DTaP) (Tripedia) for use as the fourth dose in the childhood vaccination series.

This combination vaccine will be sold under the trade name TriHIBit. On July 31, 1996, Tripedia was licensed for the initial four doses of the diphtheria, tetanus, and pertussis vaccination series. TriHIBi is the first vaccine to be licensed in the United States that combines DTaP with a Haemophilus b Conjugate Vaccine.

The Advisory Committee on Immunization Practices (ACIP), the Committee on Infectious Diseases of the American Academy of Pediatrics, and the American Academy of Family Physicians recommend that children routinely receive a series of five doses of vaccine against diphtheria, tetanus, and pertussis before age 7 years and four doses of vaccine against Haemophilus influenzae type b (Hib) disease before age 2 years (2-7).

The first four doses of the diphtheria, tetanus, and pertussis vaccination series should be administered at ages 2, 4, 6, and 15-18 months and the fifth dose at age 4-6 years. If diphtheria, tetanus, and whole-cell pertussis vaccine (DTP) is used as a fourth dose, it may be administered as early as 12 months of age provided that 6 months have elapsed since the third dose.

Because of the reduced frequency of adverse reactions and high efficacy, ACIP recommends DTaP for routine use for all doses of the pertussis vaccination series. TriHIBit can be administered as the fourth dose of the vaccination series at age 15-18 months following administration of either DTaP or DTP. TriHIBit has not been licensed for use as the first three doses of the vaccination series. Vaccine should be used immediately (within 30 minutes) after reconstitution.