A new DTPw-HB/Hib combination vaccine for primary and booster vaccination of infants in Latin America.

OBJECTIVES: In 1998 the World Health Organization (WHO) recommended the inclusion of Haemophilus influenza type B (Hib) conjugate vaccines in infant immunization programs, whenever in accordance with national priorities. GlaxoSmithKline Biologicals has developed a new pentavalent combined diphtheria-tetanus-whole cell pertussis-hepatitis B/Hib (DTPw-HB/Hib) vaccine containing 5 microg of polyribosylribitol phosphate (PRP), and we assessed the immunogenicity and reactogenicity of primary and booster vaccination of healthy children with this new vaccine compared with a reference regimen consisting of the licensed DTPw-HB (Tritanrix) and Hib (Hiberix) vaccines given as simultaneous concomitant injections.

METHODS: We performed a randomized, double-blind study from September 1998 to August 1999 to establish the immunogenicity and reactogenicity of primary and booster vaccination of healthy children with the new pentavalent combined DTPw-HB/Hib vaccine given as a single injection, compared with the reference regimen.

RESULTS: Both vaccination regimens elicited excellent immune responses, with all subjects in both groups achieving seroprotective anti-PRP antibody concentrations of > or = 0.15 microg/mL one month after primary vaccination. The combined DTPw-HB/Hib vaccine was non-inferior to the licensed vaccines in terms of seroprotection/seropositivity/vaccine response rates for all antigen components. Persistence of antibodies against all study vaccine antigens up to the time of booster vaccination was comparable between groups, and a marked increase of all antibody concentrations was observed after the booster dose. Both vaccine regimens were similar in terms of their overall reactogenicity profiles.

CONCLUSIONS: Our results indicate that the new DTPw-HB/Hib pentavalent combination vaccine provides an efficient and reliable way of implementing WHO recommendations for controlling hepatitis B and Hib infections on a worldwide basis.