Immunogenicity of a two-component (PT&FHA) acellular pertussis vaccine in various combinations

Abstract

Immunogenicity data for the pertussis components of the French diphtheria-tetanus-two component acellular pertussis vaccine (DTaP_2Fr) obtained after primary series of immunizations were compiled from 75 study groups comprising 36 clinical trials or vaccination programs conducted between 1987 and 2006. DTaP_2Fr vaccine was administered either as a standalone vaccine or as the backbone of several combination vaccines that included IPV, HepB, and/or PRP-T antigens. Most of the variability in responses was associated with differences in the schedules, and to a lesser extent the geographical region where the study was performed, suggesting the importance of ethno-ecological factors. However the addition of other vaccine antigens did not affect the immunogenicity of the aP_2Fr antigens. The immune responses to the PT and FHA antigens of the DTaP_2Fr vaccine used in the Senegal efficacy trial, which established its good efficacy relative to a highly effective DTwP vaccine, was in the middle of the range of titers observed during other studies using the 2-4-6 months schedule conducted with the same vaccine. The consistent immunogenicity of the DTaP_2Fr vaccine is accompanied by effectiveness in controlling pertussis disease in the areas where it is used on a large scale with good vaccination coverage.