Immunogenicity and safety of a combined DTaP–IPV vaccine compared with separate DTaP and IPV vaccines when administered as pre-school booster doses with a second dose of MMR vaccine to healthy children aged 4–6 years

Abstract

Combination vaccines represent one solution to the problem of increased numbers of injections during single clinic visits. A combined DTaP–IPV ( Infanrix ®-IPV) vaccine has been developed for use as a pre-school booster. Four hundred healthy children aged 4–6 years previously primed with 4 doses of DTaP vaccine ( Infanrix ®), 3 doses of poliovirus vaccine and 1 dose of MMR vaccine were randomized to receive single doses of either the combined DTaP–IPV vaccine or separate DTaP and IPV vaccines in a Phase II trial (DTaP–IPV-047). All children also received a second dose of MMR vaccine. Immunogenicity was assessed in serum samples taken before and 1 month after booster administration. Safety was actively assessed for 42 days post-vaccination. Non-inferiority of the DTaP–IPV vaccine to separate DTaP and IPV vaccines was demonstrated for all DTaP antigen booster response rates and poliovirus geometric mean titers of antibody ratios. Post-vaccination, ≥99.4% of children in both groups had seroprotective levels of anti-diphtheria and anti-tetanus antibodies (≥0.1 IU/mL) and seroprotective anti-poliovirus antibody titers (≥1:8). All children in both groups were seropositive for measles, mumps and rubella antibodies, with similar post-vaccination geometric mean concentrations/titers. No significant differences were observed in the incidence of solicited local or general symptoms, unsolicited symptoms and serious adverse events between the two groups. This combined DTaP–IPV appeared safe and immunogenic when given as a booster dose at 4–6 years of age. The DTaP–IPV vaccine had no negative effect on the response to co-administered MMR vaccine, making it well-suited for use as a pre-school booster.