Persistence Study of GSK Biologicals' Tdap Vaccine 1, 3, 5 and 9 Years Following Administration as an Initial Single Dose in Healthy Young Adults and to Evaluate the Immunogenicity and Safety of Boostrix as a Second Dose of Tdap, When Administered at Year 9

Inclusion Criteria

• Persistence follow-up phase up to Year 9 time point:

The following criteria are applicable to subjects who refuse vaccination at Year 8 time point:

All subjects who received study vaccination (Boostrix or Adacel) in study NCT00346073 will be considered eligible to participate in this study.

Written informed consent must be obtained from the subject prior to each study time point.

Vaccination phase at Year 9 applicable for subjects in Boostrix and Adacel groups only:

The following criterion is applicable to subjects willing to consent to vaccination at Year 9 time point in the Boostrix and Adacel groups:

• All subjects who received study vaccination (Boostrix or Adacel) in study NCT00346073 will be considered eligible to participate in this study.

Vaccination phase at Year 9 applicable for subjects in the Control group only:

The following criterion is applicable to subjects willing to consent to vaccination at Year 9 time point in the Control group only:

• Subjects within the age range of 28-73 years will be considered eligible to participate in this study in the Control group.

Vaccination phase at Year 9 applicable for ALL subjects (Control, Boostrix and Adacel groups):

The following criteria are applicable to subjects willing to consent to vaccination at Year 9 time point in the Boostrix, Adacel and Control groups:

All subjects must satisfy the following criteria at study entry at Year 9 time point:

Subjects who, in the opinion of the investigator, can and will comply with the requirements of the protocol (e.g. completion of the diary cards, return for follow-up visits).

Written informed consent obtained from the subject for vaccination at Year 9 time point.

Healthy subjects as established by medical history and clinical examination before entering into the study.

• Female subjects of non-childbearing potential may be enrolled in the study.
• Non-childbearing potential is defined as pre-menarche, current tubal ligation, hysterectomy, ovariectomy or post-menopause.
• Female subjects of child bearing potential may be enrolled in the study, if the subject
• has practiced adequate contraception for 30 days prior to vaccination, and
• has a negative pregnancy test on the day of vaccination, and
• has agreed to continue adequate contraception for 1 month after completion of the vaccine dose

Exclusion Criteria

The following criteria should be checked at the time of Year 9 vaccination time point. If any criteria is applicable, the subject must not be vaccinated in the study:

For subjects in Boostrix and Adacel groups:

• Administration of Tdap vaccine since the last dose received in the study NCT00346073.

For subjects in the Control group:

• Administration of Tdap (Boostrix or Adacel) vaccine at any time prior to the administration of Boostrix vaccine in this study.

For ALL subjects (Control, Boostrix and Adacel groups):

Use of any investigational or non-registered product other than the study vaccine within 30 days preceding the dose of study vaccine, or planned use during the study period, 31 days (Day 0-30).

• Chronic administration (defined as more than 14 days in total) of immunosuppressants or other immune-modifying drugs within six months prior to Visit 6 (pre-vacc). Inhaled and topical steroids are allowed.
• Planned administration/administration of a vaccine not foreseen by the study protocol in the period starting 30 days before and ending 30 days after the dose of vaccine, with the exception of inactivated Influenza vaccine which is allowed throughout the study period, 31 days (Day 0-30).

-- Concurrently participating in another clinical study, at any time during the study period, in which the subject has been or will be exposed to an investigational or a non-investigational vaccine/product.

• Hypersensitivity to latex.
• History of diphtheria, tetanus or pertussis diseases.
• Severe allergic reaction (e.g. anaphylaxis) after previous administration of any tetanus toxoid,