Immunogenicity & Reactogenicity of Boostrix 10 Years After Previous Booster Vaccination.

Inclusion Criteria: * Subjects who the investigator believes that they can and will comply with the requirements of the protocol should be enrolled in the study. * Subjects who have received dTpa vaccine or Td and pa vaccines in study 263855/004. * A male or female subject, recruited 10 years after booster vaccination in study 263855/004. * Healthy subjects as established by medical history and clinical examination before entering into the study. * If the subject is female, she must be of non-childbearing potential, or, if of childbearing potential, she must use adequate contraception for 30 days prior to vaccination and continue for 2 months after completion of the vaccination series. * Written informed consent obtained from the subject. Exclusion Criteria: * Use of any investigational or non-registered product other than the study vaccine within 30 days preceding the booster dose of study vaccine, or planned use during the study period. * Chronic administration of immunosuppressants or other immune-modifying drugs within six months prior to the booster dose. * Administration of a vaccine not foreseen by the study protocol within 30 days prior to booster vaccination or planned administration during the active study period. * 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 product. * Previous booster vaccination against tetanus, diphtheria or pertussis since the last dose received in study 263855/004. * History of documented diphtheria, tetanus, or pertussis diseases. * Any confirmed or suspected immunosuppressive or immunodeficiency condition, based on medical history and physical examination. * History of allergic disease or reactions likely to be exacerbated by any component of the vaccine. * Administration of immunoglobulins and/or any blood products within the three months preceding the booster dose or planned administration during the study period. * Occurrence of transient thrombocytopenia or neurological complications following an earlier immunisation against diphtheria and/or tetanus. * Occurrence of any of the following adverse event after a previous administration of a DTP vaccine : * hypersensitivity reaction to any component of the vaccine, * encephalopathy of unknown aetiology occurring within 7 days following previous vaccination with pertussis-containing vaccine, * fever \>= 40°C within 48 hours of vaccination not due to another identifiable cause, * collapse or shock-like state (hypotonic-hyporesponsiveness episode) within 48 hours of vaccination, * convulsions with or without fever, occurring within 3 days of vaccination. * Acute disease at the time of enrolment. * Pregnant or lactating female. * Female planning to become pregnant or planning to discontinue contraceptive precautions within 2 months after completion of the vaccination series.