Primary vaccination of infants with diphtheria-tetanus-acellular pertussis-hepatitis B virus-inactivated polio virus and Haemophilus influenzae type b vaccines given as either separate or mixed injections

Objective: The aim of this open, multicenter, randomized trial was to evalu ate the immunogenicity and reactogenicity of a candidate combined diphtheri a-tetanus-acellular pertussis-hepatitis B virus-inactivated polio virus (DT aP-HBV-IPV) vaccine when given as either a mixed or as separate concomitant injections with Haemophilus influenzae type b (Hib) vaccine. Study design: A total of 359 subjects were randomized to receive either DTa P-HBV-IPV/Hib (mixed administration - 180 subjects) or DTaP-HBV-IPV + Hib ( separate administration in opposite limbs - 179 subjects) at 2, 3, and 4 mo nths of age. Results: After vaccination, seroprotective antibody concentrations against diphtheria, tetanus, hepatitis B, and polio viruses and a high (greater tha n or equal to 97%) pertussis vaccine response were seen in almost all study participants. All subjects except one in the mixed administration group ha d postvaccination Hib anti-PRP antibody concentrations greater than or equa l to 0.15 mu g/mL. Of subjects in the mixed and separate group, 77.2% (geom etric mean antibody concentration, 2.62 mu g/mL) and 88.6% (geometric mean antibody concentration, 4.45 mu g/mL) had Hib anti-PRP concentrations great er than or equal to 1 mu g/mL, respectively. The addition of the Hib compon ent to the 5-component vaccine did not increase the incidence of local or g eneral reactions. Conclusion: Both administrations of the candidate vaccine were found to be safe, immunogenic, and well tolerated. Although anti-PRP geometric mean ant ibody concentrations and the percent of subjects achieving the 1 mu g/mL, s eroprotective level were lower after the mixed administration, they were in the range seen with monovalent Hib vaccines or with other DTaP-based/Hib c ombinations licensed in some European countries. Therefore both administrat ions have the potential to simplify childhood immunization.