Repeated administration of a reduced-antigen-content diphtheria-tetanus-acellular pertussis and poliomyelitis vaccine (dTpa-IPV; Boostrix™ IPV).

Background: The rising incidence of pertussis amongst adults and adolescents in industrialised countries could be reduced by replacing tetanus and diphtheria (Td) boosters with reduced-antigen-content dT-acellular pertussis (dTpa) vaccines. Repeated administration of a dTpa-IPV (dTpa-inactivated poliomyelitis; Boostrix™ Polio, GlaxoSmithKline) booster to adolescents, 5 years after their previous dose was evaluated. Methods: 415 subjects (mean age 11.4 years) who had received either dTpa-IPV or dTpa + IPV at age 4-8 years, all received one dose of dTpa-IPV in this open, phase IV trial. Blood samples were taken before and one-month post-vaccination. Antibody concentrations against D, T, pertussis toxoid (PT), filamentous haemagglutinin (FHA), pertactin (PRN) and polio antigens were determined. Reactogenicity and safety was assessed. Results: Before the second dTpa-IPV booster, the percentage of subjects who were seroprotected/seropositive was: 98.2% (D); 98.5% (T); 40.6% (PT); 99.7% (FHA); 97.0% (PRN); 98.8...