The Immunogenicity and Safety of a Combined DTaP-IPV//Hib Vaccine Compared with Individual DTaP-IPV and Hib (PRP~T) Vaccines: a Randomized Clinical Trial in South Korean Infants.

Recommended infant vaccination in Korea includes DTaP-IPV and Hib vaccines administered as separate injections. In this randomized, open, controlled study we assessed the non-inferiority of immunogenicity of DTaP-IPV//Hib pentavalent combination vaccine (Pentaxim™) compared with licensed DTaP-IPV and Hib (PRP~T) vaccines. We enrolled 418 healthy Korean infants to receive either separate DTaP-IPV and Hib vaccines (n = 206) or the pentavalent DTaP-IPV//Hib (n = 208) vaccine at 2, 4, 6 months of age. Antibodies to all components were measured before the first vaccination and one month after the third, and safety was assessed after each vaccination including recording of reactions by parents. We confirmed the non-inferiority of DTaP-IPV//Hib compared with DTaP-IPV and Hib vaccines; 100% of both groups achieved seroprotection against D, T, IPV and PRP~T, and 97.5%-99.0% demonstrated seroresponses to pertussis antigens. Antibody levels were similar in both groups, except for those to the Hib component, PRP~T. In separate and combined groups geometric mean concentrations of anti-PRP~T antibodies were 23.9 and 11.0 µg/mL, respectively, but 98.3% and 97.4% had titers ≥ 1 µg/mL, indicative of long-term protection. All vaccines were well tolerated, with no vaccine-related serious adverse event. Both groups had similar safety profiles, but the combined vaccine group had fewer injection site reactions. The immunological non-inferiority and similar safety profile of DTaP-IPV//Hib vaccine to separate DTaP-IPV and Hib vaccines, with the advantage of fewer injections and injection site reactions, supports the licensure and incorporation of DTaP-IPV//Hib into the Korean national vaccination schedule (Clinical trial registry, NCT01214889).

Immunogenicity and safety of a combined diphtheria, tetanus, acellular pertussis, and inactivated poliovirus vaccine (DTaP-IPV) compared to separate administration of standalone DTaP and IPV vaccines: a randomized, controlled study in infants in the Republic of Korea.

This randomized trial enrolled 442 infants in the Republic of Korea to assess the immunogenicity and safety of a combined diphtheria, tetanus, acellular pertussis, and inactivated poliovirus vaccine (DTaP-IPV; Tetraxim™) for primary vaccination at 2, 4 and 6 months of age compared with DTaP and IPV vaccines given separately. Immunogenicity was high in both groups; seroprotection and seroconversion rates of the combined vaccine (Group A) were non-inferior to the control vaccines (Group B). All subjects were seroprotected against poliovirus types 1, 2 and 3 (≥ 81/dil) and anti-diphtheria (≥ 0.01 IU/mL); 99.0% were seroprotected against tetanus (≥ 0.1 IU/mL). At least 93.6% had anti-diphtheria antibody titers ≥ 0.1 IU/mL. Anti-pertussis toxoid (PT) and anti-filamentous haemagglutinin (FHA) seroconversion (≥ 4-fold increase in antibody titer) rates were 96.6% and 94.4% for Group A, 92.2% and 78.4% for Group B. Most solicited reactions occurred within 4 days of vaccination, resolved within 3 days and were mild. Severe solicited reactions occurred after ≤ 0.5% of doses in Group A and ≤ 0.9% in Group B. No withdrawals occurred because of adverse events. The DTaP-IPV combined vaccine given at 2, 4, and 6 months of age was well tolerated; immunogenicity was similar to the control vaccines.