A Study of the Safety and Effectiveness of Two New Malaria Vaccines

This study aims to test the safety of two new malaria vaccines AdCh63 MSP1 and MVA MSP1. These vaccines consist of inactivated viruses which have been modified - so they cannot reproduce (replicate) in humans, and also to include genetic material (genes) for malaria proteins which are expressed by the malaria parasite during blood stage infection. The vaccines are designed to stimulate an immune response to these malaria proteins (immunogenicity describes the nature and magnitude of this immune response), to provide protection against malaria infection. This protection has been demonstrated in nonhuman studies. Although these vaccines have not been given to humans before, similar vaccines using the same viruses with different malaria genes have been given to humans before. In these studies, the vaccines have been shown to be safe. They have also provided evidence from laboratory tests of immunogenicity. In this study the investigators main aim is to ensure these new vaccines given alone and in combination are safe. The investigators will increase the dose of the first vaccine (AdCh63 MSP1) given to volunteers if the initial dose is safe. The investigators also wish to ensure that challenging a small number of volunteers who have received both vaccines with malaria infection from the bites of infected mosquitos(sporozoite challenge) is safe. Sporozoite challenge has been widely used in humans to test the effectiveness of malaria vaccines and is considered a well established, reliable, predictable and safe system.In the study the investigators will also look for evidence of immunogenicity of these new vaccines, and whether there is any delay to developing malaria following sporozoite challenge. The study will be conducted at the University of Oxfords Centre for Clinical Vaccinology and Tropical Medicine (CCVTM). The challenge part of the study will take place at the insectary at Imperial College, (Infection and Immunity Section)in London.