The purpose of study Td519 is to demonstrate that Adacel® vaccine (Tetanus Toxoid, Reduced Diphtheria Toxoid and Acellular Pertussis Adsorbed) is safe and immunogenic in persons 10 years of age.

Primary Objectives:

• To compare pertussis antibody responses induced by Adacel® in persons 10 to <11 years of age to those induced by Adacel in persons 11 to <12 years of age.
• To compare the booster responses against pertussis antigens induced by Adacel in persons 10 to <11 years of age to those induced by Adacel in persons 11 to <12 years of age.
• To compare booster responses against tetanus and diphtheria induced by Adacel in persons 10 to <11 years of age to those induced by Adacel in persons 11 to <12 years of age.

Secondary Objective:

• To compare seroprotection rates against tetanus and diphtheria induced by Adacel in persons 10 to <11 years of age to those induced by Adacel in persons 11 to <12 years of age.

Study participants will receive a single dose of study vaccine and will then be monitored for safety from the day of vaccination for up to 30 days post-vaccination.

Inclusion Criteria:

• Age is > 10 to < 12 years of age at the time of vaccination.
• Assent form has been signed and dated by the subject, and informed consent has been signed and dated by the parent(s) or another legally acceptable representative (and by an independent witness if required by local regulations).
• Subject and parent/guardian are able to attend all scheduled visits and to comply with all trial procedures.
• For a female of childbearing potential, abstinence or use of an effective method of contraception from at least 4 weeks prior to vaccination until at least 4 weeks after vaccination.
• Documented vaccination history of receiving 5 previous doses of DTaP (combination diphtheria, tetanus, and acellular pertussis) vaccine (consisting of 3 infant doses in the first year of life, a 4th dose in the 2nd year of life, and a 5th dose at 4 through 6 years of age).

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, acute, or chronic disease that is unstable or that, in the opinion of the Investigator, might: (i) interfere with the ability to participate fully in the study; or (ii) interfere with evaluation of the vaccine.
• Known or suspected congenital or acquired immunodeficiency; or receipt of immunosuppressive therapy such as anti-cancer chemotherapy or radiation therapy within the preceding 6 months; or long-term systemic corticosteroid therapy (prednisone or equivalent for more than 2 consecutive weeks within the past 3 months).
• Prior receipt of pertussis, diphtheria, or tetanus containing vaccines within the past 5 years.
• A personal history of physician-diagnosed or laboratory confirmed pertussis disease within the last 2 years.
• A previous severe reaction to pertussis, diphtheria or tetanus vaccine including immediate anaphylaxis, encephalopathy within 7 days or seizure within 3 days of receiving the vaccine.
• Receipt of blood or blood-derived products in the past 3 months, which might interfere with the assessment of the immune response.
• History of allergy to egg proteins, latex, or any constituents of the vaccine.
• Suspected or known hypersensitivity to any of the vaccine components, or history of a life-threatening reaction to the vaccine used in the trial or to a vaccine containing any of the same substances.
• Receipt of any vaccine within 30 days before receiving study vaccine, or plans to receive another vaccine before the 2nd visit; except that influenza vaccine may have been received between 30 and 15 days (but no less than 15 days) before receiving study vaccine.
• Participation in another interventional clinical trial investigating a vaccine, drug, medical device, or medical procedure in the 30 days preceding the first study vaccination or during the course of the study.
• Seropositivity for Human Immunodeficiency Virus (HIV), Hepatitis B, or Hepatitis C, as reported by the parent/guardian.
• Laboratory-confirmed thrombocytopenia, bleeding disorders, or receipt of anticoagulants in the 3 weeks preceding inclusion, contraindicating intramuscular vaccination, at the discretion of the Investigator.
• Known pregnancy, or a positive urine or serum pregnancy test.
• Prior personal history of Guillain-Barré syndrome.
• Identified as an investigator or employee of the investigator or study center with direct involvement in the proposed study, or identified as an immediate family member (i.e., parent, spouse, natural or adopted child) of the investigator or employee with direct involvement in the proposed study.