This is an open label phase I study, to assess the safety of a novel malaria vaccine, AdCh63 AMA1, simian adenovirus encoding Plasmodium falciparum blood stage antigen, Apical Membrane Antigen -1. All volunteers recruited will be healthy adults. They will be primed with various doses of AdCh63 AMA1 administered intramuscularly. Some of the volunteers will receive a booster vaccination with MVA AMA1 administered via intramuscular route. Safety data will be collected for each of the eight regimens. Secondary aims of this study will be to assess the immune responses generated by each of these regimes.