Immunogenicity and safety of a tetravalent diphtheria-tetanus-acellular pertussis-inactivated poliovirus vaccine.

The objective of this study was to investigate whether a tetravalent vaccine containing diphtheria, tetanus, monocomponent acellular pertussis and inactivated poliovirus (DTaP-IPV) was immunogenic and safe compared with the vaccination regime used in Denmark at the time of the study. The study was performed as an open controlled study in which 270 Danish children were enrolled at their 5 weeks' routine examination. The children were allocated to receive either (i) DTaP-IPV (12.5 Lf, 7 Lf, 40 microg, 40, 8, 32 DU) at 3, 5 and 12 months of age (n = 186) or (ii) DT-IPV (50 Lf, 12.5 Lf, 40, 8, 32 DU) at 5, 6 and 15 months of age plus whole-cell pertussis vaccine (> or = 4 IU) at 5 and 9 weeks and at 10 months of age (n = 84). No hypotonic hyporesponsive episodes or other vaccine-related serious adverse events were seen. Local reactions, febrile and crying episodes with the investigational vaccine (DTaP-IPV) were similar to the reactions seen with the existing DT-IPV vaccine. One month after completing the vaccination schedule, all children had antibodies above the defined protective antibody concentrations to polio, tetanus and diphtheria. For pertussis toxin, there was a significantly better response in the investigational vaccine group. We therefore conclude that, when used according to the schedule tested, the tetravalent DTaP-IPV vaccine is safe and immunogenic. In addition, the number of visits and the number of injections necessary are reduced with this vaccine and vaccination schedule.