A liquid hexavalent combined vaccine against diphtheria, tetanus, pertussis, poliomyelitis, Haemophilus influenzae type B and hepatitis B: review of immunogenicity and safety.

To reduce the number of injections needed to comply with paediatric vaccination requirements, a liquid, hexavalent vaccine (DTaP–IPV–PRP-T–HBs; Hexavac®; Aventis Pasteur MSD) has been developed for primary and booster vaccination of infants and toddlers. In extensive clinical studies, Hexavac® has been shown to be highly immunogenic. Seroconversion or seroprotective titres of antibodies against all antigens were achieved in the majority of infants following a primary series of three doses administered at 1–2-month intervals from 2 months of age. Hexavac® also induced immunologic memory, as evidenced by the anamnestic response to booster vaccination at 12–18 months of age. These responses were comparable with those seen following concomitant administration of Pentavac™ (DTaP–IPV//PRP-T) and monovalent hepatitis B vaccine (H-B-Vax® II), and were also within the ranges observed for other relevant licensed vaccines. Clinical studies comparing the immunogenicity of Hexavac® administered at either 2, 3 and 4 months or 2, 4 and 6 months demonstrated that it can be used by either vaccination schedule. A further study also supported the use of primary doses of Hexavac® at 3 and 5 months with a booster at 12 months of age. Hexavac® demonstrated a good reactogenicity and tolerability profile. The most frequently reported adverse events after both primary and booster doses were local reactions of redness and swelling/induration and a systemic response of mild fever, irrespective of the vaccine used for priming. Hexavac® provided immunity against six important childhood diseases with a single injection at each visit.