Immunogenicity and safety of an acellular pertussis, diphtheria, tetanus, inactivated poliovirus, Hib-conjugate combined vaccine (Pentaxim) and monovalent hepatitis B vaccine at 6, 10 and 14 weeks of age in infants in South Africa.

Objective: To assess the immunogenicity and safety data for a pentavalent combination vaccine containing acellular pertussis, inactivated poliovirus, and Haemophilus influenzae (Hib) polysaccharide-conjugate antigens.

Methods: A DTaP-IPV//PRP T vaccine (Pentaxim) was given at 6, 10 and 14 weeks of age to 212 infants in South Africa. Monovalent hepatitis B vaccine was given concomitantly. Immunogenicity was assessed using seroprotection and seroconversion rates; safety was assessed by monitoring for solicited injection site and systemic adverse events, and follow-up monitoring for unsolicited adverse events and serious adverse events.

Results: Immunogenicity was high for each vaccine antigen, and similar to a reference study done in France using a similar (2, 3 and 4 months of age) administration schedule. After the third dose, 94.6% of participants had anti-PRP > or = 0.15 microg/ml. The anti-PRP geometric mean antibody titre (GMT) was 2.0 microg/ml. The seroprotection rates for diphtheria and tetanus (> or = 0.01 IU/ml), poliovirus types 1, 2 and 3 (> or = 8 1/dil U) and hepatitis B were all 100%. Anti-polio GMTs were very high, 1 453, 1 699 and 2 398 (1/dil U) for types 1, 2 and 3, respectively. The seroconversion/vaccine response rates to pertussis antigens (4-fold increase in antibody concentration) were 97.5% for PT and 83.9% for FHA.

Conclusions: The DTaP-IPV//PRP T vaccine was highly immunogenic at 6, 10 and 14 weeks of age in infants in South Africa, was compatible with the monovalent hepatitis B vaccine, and was well tolerated.