A Bridging Study to Evaluate the Safety and Immunogenicity of GSK Biologicals' Candidate Vaccines RTS,S/AS02D (0.5 mL Dose) and RTS,S/AS02A (0.25 mL Dose) Administered According to a 0, 1, 2 Month Vaccination Schedule in Children Aged 3 to 5 Years Living in a Malaria-endemic Region of Mozambique.

GSK Biologicals is developing in partnership with the Malaria Vaccine Initiative at PATH a candidate malaria vaccine RTS,S/AS02 for the routine immunization of infants and children living in malaria endemic areas. The vaccine would offer protection against malaria disease due to the parasite Plasmodium falciparum and also would provide protection against infection with hepatitis B virus. Studies conducted using the formulation RTS,S/AS02A (0.25 ml dose) in children and adults have shown to be safe. Currently all intramuscular vaccines in the EPI schedule are administered at a dose volume of 0.5 ml and in this context, a new variant of RTS,S/AS02D (0.5 ml dose) formulation has been composed which has the same active constituents in the same quantities as in a 0.25 ml dose of RTS,S/AS02A. In this study, RTS,S/AS02D (0.5 ml dose) was compared to the existing formulation, RTS,S/AS02A (0.25 ml dose).