Post-licensure, Modified Double-blind, Multi-center Study Evaluating Safety and Immunogenicity of ADACEL® and BOOSTRIX®

Inclusion Criteria: * Aged 11 - 18 years of age at the time of vaccination in this trial * Signed Institutional Review Board (IRB)-approved informed assent / consent form. * Able to attend all scheduled visits and to comply with all trial procedures. * For a female, negative serum/urine pregnancy test. Exclusion Criteria: * Any condition which, in the opinion of the investigator, would pose a health risk to the participant or interfere with the evaluation of the vaccine. * Serious chronic disease (i.e. cardiac, renal, neurologic, metabolic, rheumatologic, psychiatric etc) that is unstable or that might: * interfere with the ability to participate fully in the study; or * interfere with evaluation of the vaccine. * Known or suspected impairment of immunologic function. * Febrile illness within the last 72 hours or an oral temperature ≥ 100.4°F (≥ 38°C) at the time of inclusion. * History of documented tetanus, diphtheria or pertussis disease within the preceding 5 years. * Known or suspected receipt of a tetanus or diphtheria-containing vaccine within the preceding 2 years. * Known or suspected receipt of a pertussis-containing vaccine within the preceding 5 years. * Administration of immune globulin or other blood products within the last three months, or injected or oral corticosteroids or other therapy expected to materially alter immune function within six weeks of the study vaccine. Individuals on a tapering dose schedule of oral steroids lasting less than 7 days may be included in the trial as long as they have not received more than one course within the last two weeks prior to enrollment. * Received any vaccine in the 21-day period prior to enrollment or scheduled to receive any vaccination after enrollment and prior to visit 2. * Suspected or known hypersensitivity to any of the vaccine components or to latex.