Immunogenicity and reactogenicity of a bicomponent and a tricomponent acellular pertussis-diphtheria-tetanus (DTaP) vaccine in primary immunization and as second year booster: A double-blind, randomized trial

Abstract

Objectives: To compare the immunogenicities and reactogenicities of bicomponent (B) (pertussis toxoid, filamentous hemagglutinin) and tricomponent (T) (pertussis toxoid, filamentous hemagglutinin, pertactin) acellular pertussis vaccines when coadministered with diphtheria and tetanus toxoids in primary (3, 4, and 5 mo) and booster (15–19 mo) vaccinations. Design and Methods: A randomized, double-blind study involving 175 children aged 12 to 18 weeks. Reactogenicity was based on diary cards, immunogenicity assessed by ELISA measurements of serum IgG antibodies. Results: There were no clinically relevant differences in local (B = 34.5; T = 31.3%) and general (B = 43.9; T = 41.8%) reactogenicities between the two vaccines during the primary vaccinations. Booster doses caused significantly more adverse reactions than primary vaccination, but local (B = 77.6; T = 66.2%) and general (B = 64.2; T = 60.8%) reaction rates remained similar for the two vaccines. Both vaccines had almost identical immunogenicities with respect to the corresponding antigens and elicited seropositive antibody titers in 100% of the recipients of vaccines against diphtheria, tetanus, and the respective pertussis antigens 1 month after primary and booster vaccinations. Conclusions: The tricomponent vaccine was no more reactogenic than the bicomponent vaccine and at least as immunogenic for the respective antigens. Because tricomponent vaccine reliably induces antibodies to an additional antigen involved in immunoprotection, it may be preferable for use in primary as well as booster vaccination.