Primary vaccination of adults with reduced antigen-content diphtheria-tetanus-acellular pertussis or dTpa-inactivated poliovirus vaccines compared to diphtheria-tetanus-toxoid vaccines

ABSTRACTObjective: To evaluate immunogenicity and reactogenicity of primary vaccination with reduced-antigen-content diphtheria-tetanus-acellular pertussis (dTpa) or dTpa-inactivated poliovirus (dTpa‑IPV) vaccine compared to diphtheria-tetanus-toxoid vaccines (Td) in adults ≥ 40 years of age without diphtheria or tetanus vaccination for 20 years or with an unknown vaccination history.Research design and methods: Double-blind, randomized, controlled clinical trial. Primary vaccination with either three doses of dTpa, one dose of dTpa‑IPV followed by two doses of Td, or three doses of Td vaccine (control) administered in a 0‑1‑6-month schedule.Main outcome measures: Blood samples were collected before commencement and 1 month after each dose. Local and general symptoms were solicited for 15 days after each dose.Results: A total of 460 adults were enrolled, of whom over 48% did not have protective antibody concentrations against diphtheria and tetanus. One month after dose 3 > 99% had seroprotective anti-dip...