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

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

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, diphtheria toxoid, or pertussis-antigen containing vaccines, or any component of Boostrix.
• History of any neurological disorders or seizures.
• Encephalopathy (e.g. coma, decreased level of consciousness, prolonged seizures) of unknown etiology occurring within seven days following previous vaccination with pertussis-containing vaccine.
• Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination (no laboratory testing required).
• Acute disease and/or fever at the time of enrolment.

Subjects with a minor illness (such as mild diarrhea, mild upper respiratory infection) without fever may, be enrolled at the discretion of the investigator.

• Administration of immunoglobulins and/or any blood products within three months preceding the dose of study vaccine or planned administration during the study period, 31 days (Day 0-30). Administration of any tetanus or diphtheria containing vaccine or any registered or investigational vaccine utilizing a diphtheria toxoid or tetanus toxoid carrier within 5 years prior to the administration of Boostrix vaccine in this study.
• Acute or chronic, clinically significant pulmonary, cardiovascular, hepatic or renal functional abnormality, as determined by physical examination or laboratory screening tests.
• Pregnant or lactating female.
• Female planning to become pregnant or planning to discontinue contraceptive precautions during the 31 day (Day 0-30) follow-up period post-vaccination.