Bridging Safety & Immunogenicity Study of GSK Biologicals' Candidate Malaria Vaccine RTS,S/AS01E (0.5 mL Dose) to RTS,S/AS02D (0.5 mL Dose) Administered IM According to a 0, 1, 2-Month Schedule in Gabonese Children Aged 18 Months to 4 Years

GSK Biologicals is developing a number of candidate malaria vaccines for the routine immunization of infants and children living in malaria-endemic areas. The candidate vaccines are designed to offer protection against malaria disease due to the parasite Plasmodium falciparum. Candidate vaccines containing the RTS,S antigen would also provide protection against infection with hepatitis B virus (HBV). This study will evaluate two candidate vaccines. The Protocol Posting has been updated in order to comply with the FDA Amendment Act, Sep 2007.