A Study to Evaluate the Safety, Immunogenicity and Efficacy of GlaxoSmithKline (GSK) Biologicals' Candidate Malaria Vaccine RTS,S/AS02A, When Administered to Children Aged 1 to 4 Years Living in a Malaria-endemic Region of Mozambique.

Inclusion Criteria: Healthy male and female children, 1 to 4 years of age at the time of first vaccination (up to but not including 5th birthday). Written/thumbprinted and witnessed informed consent obtained from the parents or legal guardians. Exclusion Criteria: Major congenital defects or serious chronic illness. History of allergic reactions to vaccination or to any component of the Hiberix™, Prevnar® or Engerix-B™ vaccines. Chronic administration (defined as more than 14 days) of immuno-suppressants or other immune modifying drugs within six months prior to the first vaccine dose . Previous vaccination with an experimental vaccine or with hepatitis B vaccine in children equal to or more than 18 months of age. Simultaneous participation in any other clinical trial. Use of any investigational or non-registered drug or vaccine other than the study vaccine(s) within 30 days preceding the first dose of study vaccine, or planned use during the study period. Planned administration of a vaccine not foreseen by the study protocol within 30 days before the first dose of vaccine. An exception, is the receipt of an EPI or licensed vaccine. Administration of immunoglobulins and/or any blood products within the three months preceding the first dose of study vaccine or planned administration during the study period. Any confirmed or suspected immunosuppressive or immunodeficient condition, including human immunodeficiency virus (HIV) infection.