American Academy of Pediatrics Committee on Infectious Diseases: Haemophilus influenzae type b conjugate vaccines: recommendations for immunization with recently and previously licensed vaccines.

This updated statement on Haemophilus influenzae type b conjugate vaccines includes recommendations for use of a newly licensed Haemophilus conjugate vaccine, and a newly licensed combination vaccine that combines one of the Haemophilus conjugate vaccines and diphtheria, tetanus toxoids, and pertussis (DTP). The statement also includes revised guidelines for the use of all conjugate vaccines. The changes concern use of different vaccine products in children younger than 15 months of age; timing for booster doses for completion of the immunization schedule in children 12 months of age and older; schedules for children in whom vaccination has been delayed in initiation, or has lapsed; choice of vaccine in children in whom vaccination against DTP or diphtheria and tetanus toxoids (DT) is deferred; number of doses for children with immunologic impairment associated with increased risk of H influenzae type b disease; and indications for rifampin prophylaxis in households where contacts have been vaccinated. Related information on the basis for these new recommendations also is given. As of 1993, four H influenzae type b conjugate vaccines, and a combination vaccine that combines one of these vaccines with DTF are licensed in the United States. The newly licensed conjugate vaccine consists of polyribosylribitol phosphate (PRP) conjugated to tetanus toxoid (PRP-T; ActHIB/OmniHib, prepared by Institut Meneux and distributed in the United States by Connaught Laboratories and SmithKline Beecham). The combination vaccine consists of a licensed conjugate of PRP oligomers covalently linked to diphthena-CRM,97 protein (HbOC; HIBTITER) with DiP (TRI-IMMUNOL), and is referred to as HbOC-DTP (TETRAMUNE; manufactured by Lederle-Praxis). Both new vaccines are approved for use beginning at 2 months of age. The four licensed vaccines are summarized in Table I . Their composition differs in several impor-