BACKGROUND: The incidence of pertussis is increasing, especially in adolescents, attributed in part to waning of immunity after childhood immunization. Recently licensed in the United States for use in adolescents, acellular pertussis vaccines will provide an immunogenic and safe option for booster immunization against pertussis. METHODS: This prospective, randomized, observer-blinded, multicenter, comparative study evaluated the safety and immunogenicity of a vaccine formulated with tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis antigens (Tdap) compared with tetanus and diphtheria toxoids vaccine (Td) for booster immunization in adolescents. There were 4114 healthy adolescents aged 10 to 18 years who completed childhood vaccination against diphtheria, tetanus, and pertussis who were enrolled, randomized, and received study vaccine. RESULTS:Local and general symptoms were comparable between the Tdap and Td groups. The immune response of Tdap was comparable with Td vaccine for tetanus and diphtheria seroprotection and booster responses. In addition, geometric mean concentrations of antibody to pertussis antigens, pertussis toxoid, filamentous hemagglutinin, and pertactin exceeded the antibody response elicited after infant immunization with diphtheria and tetanus toxoids and acellular pertussis antigens (DTaP) that had proven efficacy against pertussis. CONCLUSIONS: In adolescents, the studied Tdap was safe and immunogenic and induced pertussis antibodies that were higher than those associated with efficacy in infants.
RCT Entities:
BACKGROUND: The incidence of pertussis is increasing, especially in adolescents, attributed in part to waning of immunity after childhood immunization. Recently licensed in the United States for use in adolescents, acellular pertussis vaccines will provide an immunogenic and safe option for booster immunization against pertussis. METHODS: This prospective, randomized, observer-blinded, multicenter, comparative study evaluated the safety and immunogenicity of a vaccine formulated with tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis antigens (Tdap) compared with tetanus and diphtheria toxoids vaccine (Td) for booster immunization in adolescents. There were 4114 healthy adolescents aged 10 to 18 years who completed childhood vaccination against diphtheria, tetanus, and pertussis who were enrolled, randomized, and received study vaccine. RESULTS: Local and general symptoms were comparable between the Tdap and Td groups. The immune response of Tdap was comparable with Td vaccine for tetanus and diphtheria seroprotection and booster responses. In addition, geometric mean concentrations of antibody to pertussis antigens, pertussis toxoid, filamentous hemagglutinin, and pertactin exceeded the antibody response elicited after infant immunization with diphtheria and tetanus toxoids and acellular pertussis antigens (DTaP) that had proven efficacy against pertussis. CONCLUSIONS: In adolescents, the studied Tdap was safe and immunogenic and induced pertussis antibodies that were higher than those associated with efficacy in infants.