On Jun. 9, 2005, the U.S. Food and Drug Administration (FDA) licensed a 2nd Tdap vaccine (Adacel by Sanofi Pasteur) for use in persons ages 11-64 years.

Adacel vaccine provided demonstrated immunogenicity against tetanus, diphtheria, and pertussis, and has a safety profile similar to that of tetanus-diphtheria (Td) vaccine.