Safety and Immunogenicity in Adults of Revaccination With Adacel® Vaccine 10 Years After a Previous Dose

Healthy adults < 65 years of age who received Adacel vaccine 10 years previously will be
randomized to receive either Adacel or TENIVAC (Td Adsorbed) vaccine. They will be assessed
for immunogenicity at baseline and post-vaccination. Safety data will be collected for 6
months following vaccination.

Inclusion criteria:

- Subject is ≥ 18 to < 65 years of age at the time of vaccination.

- Received Adacel vaccine no less than 9 and no more than 11 years previously.

- Informed consent form has been signed and dated.

- Subject is able to attend all scheduled visits and to comply with all trial
procedures.

Exclusion criteria:

- Subject is pregnant, or lactating, or of child bearing potential without using an
effective method of contraception or not practicing abstinence for at least 4 weeks
prior to vaccination and until at least 4 weeks after vaccination. Females who are
pre-menarche or post-menopausal for at least one year, or surgically sterile will not
be excluded.

- Any condition that, in the opinion of the Investigator, would pose a health risk to
the participant or interfere with the evaluation of the vaccine.

- Chronic illness that, in the opinion of the Investigator, is at a stage where it might
interfere with trial conduct or completion.

- 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).

- Known or suspected receipt of tetanus toxoid (T), tetanus and diphtheria toxoids (Td),
or tetanus and diphtheria toxoids and acellular pertussis (Tdap) vaccine since receipt
of the qualifying dose of Adacel vaccine described in Inclusion Criterion #2.

- A personal history of physician-diagnosed or laboratory-confirmed pertussis disease
within the last 10 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 immune globulins, blood or blood-derived products in the past 3 months.

- 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, at the discretion of the Sponsor.

- Seropositivity for Human Immunodeficiency Virus (HIV), Hepatitis B, or Hepatitis C, as
reported by the subject.

- Laboratory-confirmed thrombocytopenia, which may be a contraindication for IM
vaccination, at the discretion of the Investigator.

- Bleeding disorder or receipt of anticoagulants in the 3 weeks preceding inclusion,
which may be a contraindication for intramuscular (IM) vaccination, at the discretion
of the Investigator.

- Personal history of Guillain-Barré syndrome.

- Moderate or severe acute illness/infection (according to Investigator judgment) or
febrile illness (temperature ≥ 38.0°C [≥ 100.4°F]) on the day of vaccination. A
prospective subject should not be enrolled in the study until the condition has
resolved or the febrile event has subsided.

- 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.

- Deprived of freedom by an administrative or court order, or in an emergency setting,
or hospitalized involuntarily.

- Current alcohol or drug use that, in the opinion of the Investigator, might interfere
with the ability to comply with trial procedures.