On Apr. 1, 2014, Sanofi Pasteur announced the U.S. Food and Drug Administration (FDA) had expanded the approved age indication of Adacel (Tetanus Toxoid, Reduced Diphtheria Toxoid and Acellular Pertussis Vaccine Adsorbed; Tdap) for active booster immunization for the prevention of tetanus, diphtheria, and pertussis as a single dose in persons 10 through 64 years of age.

The FDA approval was based on data from a Phase IV, open label, multi-center trial to evaluate the safety and immunogenicity of a single dose of Adacel vaccine in persons 10 years of age compared with those in persons 11 years of age. Antibody responses to all of the vaccine antigens (tetanus, diphtheria, and pertussis) and rates of adverse reactions were similar in the two age groups.