Inclusion Criteria:

• Participant is healthy as per medical history reported by subject.
• Participant is at least 11 years of age at the time of vaccination.
• Participant has a signed Institutional Review Board (IRB)-approved informed assent/consent form. For subjects 11 to 17 years of age, a written informed consent must be obtained from parent(s) or legal guardian(s) and a written informed assent must be obtained from the subject
• Participant provides history or documentation of primary or booster immunization with Diphtheria and Tetanus.
• Female participants of childbearing potential must have a negative urine pregnancy test at the time of enrollment.

Exclusion Criteria:

• Serious and uncontrolled chronic disease (i.e., cardiac, pulmonary, renal, neurologic, metabolic, rheumatologic, etc.).
• Known or suspected impairment of immunologic function.
• Acute medical illness with or without fever within the last 72 hours or an oral temperature ³100.4°F (³38°C) at the time of enrollment.
• Administration of immune globulin or other blood products within the last three months; administration of corticosteroids (injected or oral) or other immunomodulatory therapy within six weeks of the study vaccine. However, individuals on a tapering dose schedule of oral steroids may be included in the trial, as long as steroids were discontinued more than two weeks prior to enrollment.
• Received any vaccine, other than influenza vaccine, in the 28-day period prior to enrollment or scheduled to receive any vaccination, other than influenza prior to Visit 2 blood draw. For influenza vaccine only, exclude if received in the 14 day period prior to enrollment or scheduled to receive in the 14 day period after Visit 1.
• Suspected or known hypersensitivity to Td components, thimerosal (for subjects > 60 years of age) or latex rubber.
• Unable to attend scheduled visits or unable to comply with the study procedures.
• Enrolled in another clinical trial.
• Any condition that would pose a health risk to the participant or interfere with the evaluation of the vaccine in the opinion of the investigator.
• A positive urine pregnancy test at the time of enrollment for all females of childbearing potential.
• Female of childbearing potential who does not agree either to remain abstinent or to use effective birth control during the period of the trial.
• Breast feeding during the period of the trial.
• A history of Guillain- Barré syndrome within 6 weeks after a previous dose of tetanus toxoid-containing vaccine.
• Receipt of a tetanus or diphtheria vaccination within the 5 years prior to enrollment.
• A previous history of diphtheria disease within the last 25 years or tetanus disease
• History of Arthus-type hypersensitivity reaction or a temperature >103° F following a prior dose of tetanus toxoid, unless 10 years have elapsed since the previous dose.