Assess Reacto- and Immunogenicity of Pneumococcal Conjugate Vaccine When Given as Booster or a 2 Dose Catch up Schedule

Phase II, Observer-blind Follow-up Study to Assess reacto-and Immunogenicity of GSK Biologicals' Pneumococcal Conjugate Vaccine (GSK1024850A), When Given as Booster in Primed Children or as 2-dose Catch-up in Unprimed Children.

This is a booster study in 2 groups of healthy children less than 3 years old to measure the reactogenicity, safety and immunogenicity of GSK Biologicals' pneumococcal conjugate vaccine, when given as a booster or as a two-dose catch-up vaccination.

This protocol posting deals with objectives and outcome measures of the booster phase. The objectives and outcome measures of the primary phase are presented in a separate protocol posting (NCT number = NCT00338351).

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

Inclusion Criteria:

• Male or female between, and including, 18-21 months of age at the time of vaccination.
• Subjects who previously participated in the primary study and received 3 doses of study or control vaccines during the primary study.
• Subjects for whom the investigator believes that their parents/guardians can and will comply with the requirements of the protocol.
• Written informed consent obtained from the parent or guardian of the subject.
• Free of obvious health problems as established by medical history and clinical examination before entering into the study.

Exclusion Criteria:

• Use of any investigational or non-registered drug or vaccine other than the study vaccine(s) within 30 days preceding the booster doses of study vaccines, or planned use during the study period (active phase and extended safety follow-up).
• Planned administration/ administration of a vaccine not foreseen by the study protocol during the period starting one month (30 days) before the booster doses of vaccine(s) and during the active phase of the study (up to the follow-up visit (Visit 3)).
• History of allergic disease or reactions likely to be exacerbated by any component of the vaccines.
• History of seizures (subjects who have had a single, uncomplicated febrile convulsion in the past can be included) or progressive neurological disease.
• Acute disease at the time of enrolment.
• Chronic administration (defined as more than 14 days) of immunosuppressants or other immune-modifying drugs within 6 months prior to the booster doses of study vaccines.
• Any confirmed or suspected immunosuppressive or immunodeficient condition based on medical history and physical examination.
• A family history of congenital or hereditary immunodeficiency.
• Major congenital defects or serious chronic illness.
• Administration of immunoglobulins and/or any blood products within the last 3 months prior to booster or follow-up vaccination or planned administration during the active phase of the study.