Study to Asses DTPw-HBV/Hib at 15-18 Months (m) and Mencevax™ ACW at 24 to 30 m in Primed Subjects

The purpose of this study is to assess the safety and reactogenicity of a booster dose of diphtheria-tetanus-whole cell pertussis-hepatitis B virus/Haemophilus influenzae type b vaccine (DTPw-HBV/Hib) at 15-18 m and to assess the immunogenicity, safety, and reactogenicity of a dose of Mencevax™ Group A, C and W135 polysaccharide meningococcal vaccine (ACW) at 24 to 30 m in primed subjects.

The Protocol Posting has been updated in order to comply with the FDA Amendment Act, Sep 2007.

This open study will have two parallel groups based on the vaccination received in the primary study: AC primed Group: primed with Tritanrix™-HepB/Hib-MenAC vaccine and AC unprimed Group (control): primed with Tritanrix™-HepB/Hiberix™ vaccine. All subjects will receive a booster dose of Tritanrix™-HepB/Hiberix™ vaccine at 15 to 18 months of age with GSK Biological's OPV vaccine given concomitantly and a dose of Mencevax™ ACW vaccine at 24 to 30 months of age. Blood sampling will be done prior to (pre) and one month after (post) the Mencevax™ ACW vaccine administration for immunogenicity analyses. The study will last minimum 7 to maximum 16 months per subject.

Mencevax™ ACWY was changed to Mencevax™ ACW throughout the posting to correct an inconsistency in the earlier version of the protocol posting and to reflect the actual situation.

Eligibility Criteria:
Inclusion Criteria:

* Subjects who the investigator believes that their parents/guardians can and will comply with the requirements of the protocol.
* A male or female between, and including, 15 and 18 months of age at the time of vaccination.
* Written informed consent obtained from the parent or guardian of the subject.
* Healthy subjects as established by medical history and clinical examination before entering into the study.
* Having participated in the primary vaccination study (CPMS N° 759346/007).

Exclusion criteria:

* Use of any investigational or non-registered product (drug or vaccine) other than the study vaccine within 30 days preceding the vaccination, or planned use during the study period.
* Chronic administration (defined as more than 14 days) of immunosuppressants or other immune-modifying drugs within six months prior to vaccination.
* Planned administration/ administration of a vaccine not foreseen by the study protocol within 30 days of vaccination.
* Booster vaccination against diphtheria, tetanus, pertussis, hepatitis B, Haemophilus influenzae type b (Hib) and/or meningococcal serogroups A, C or W disease, after the date of the study conclusion visit of the primary vaccination study (CPMS N° 759346/007).
* History of diphtheria, tetanus, pertussis, hepatitis B, Hib and/or meningococcal serogroup A, C or W disease.
* Known exposure to diphtheria, tetanus, pertussis, hepatitis B, Hib and/or meningococcal serogroup A, C or W disease.
* Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination.
* A family history of congenital or hereditary immunodeficiency.
* History of allergic disease or reactions likely to be exacerbated by any component of the vaccines administered in the study.
* Major congenital defects or serious chronic illness.
* History of any neurologic disorders or seizures including febrile seizures in infancy.
* Acute disease at the time of enrolment.
* Axillary temperature ≥ 37.5°C at the time of vaccination.
* Administration of immunoglobulins and/or any blood products within the three months preceding the vaccination or planned administration during the study period.
* Anaphylactic reaction following the administration of vaccine in the primary vaccination study.
* Known hypersensitivity to any component of the vaccine, or subjects having shown signs of hypersensitivity after previous administration of diphtheria, tetanus, pertussis, hepatitis B, Hib or meningococcal vaccines.