-Prior receipt of a tetanus or diphtheria-containing vaccine within two years of enrollment. -Prior receipt of a tetanus and diphtheria toxoid and acellular pertussis vaccine within two years of enrollment. -Known or suspected impairment of immunologic function. -Febrile illness within the last 24 hours or an oral temperature >/= 100.4 degrees F (>/= 38 degrees C) at the time of enrollment. -History of documented tetanus, diphtheria, or pertussis disease within the preceding 5 years. -History of allergic or adverse reaction to diphtheria, tetanus, or pertussis vaccines. -Receipt of any steroids, immunoglobulins, other blood products/transfusion within the past six months- excluding Rh immunoglobulin (Rhogam™ and Rhophylac™). -Is enrolled or plans to enroll in another clinical trial with an investigational product while participating in this study (observational studies are allowed). -Known active infection with HIV, hepatitis B, or hepatitis C. -History of alcohol or drug abuse in the last 5 years. -Any condition which, in the opinion of the investigators, may pose a health risk to the subject or interfere with the evaluation of the study objectives. -Any woman with health condition who is currently taking glucocorticoids, i.e., oral, parenteral, and high-dose inhaled steroids, and immunosuppressive or cytotoxic drugs. -Sensitive to latex, based on package insert -Progressive or unstable neurologic condition, based on package insert. -Receipt of influenza or other vaccines concomitantly administered or for 42 days following Adacel, based on package insert.