A Safety and Efficacy Study of Concomitant Administration of ChAd63/MVA ME-TRAP + RTS,S

The purpose of this study is to assess two types of new malaria vaccines in different combinations. The study will enable us to assess: 1. The ability of the vaccines to prevent malaria infection. 2. The safety of the vaccines in healthy participants. 3. The response of the human immune system to the vaccines. We will do this by giving 48 participants three sets of vaccinations over 8 weeks, then exposing them to malaria infection by allowing mosquitoes infected with malaria to bite under carefully regulated conditions. We will follow participants closely to observe if and when they develop malaria. If the vaccine combination provides some protection against malaria, participants will take longer to develop malaria than usual or will not develop malaria at all. We will also recruit 4 individuals to be control subjects - these participants won't receive any vaccinations but will be challenged with malaria. Vaccinated volunteers who do not develop malaria infection in the blood after being infected with malaria by mosquito bite the first time may be invited back to be again infected with malaria in a repeat challenge experiment. This would happen approximately 5-7 months after the first challenge. The purpose of this second challenge will be to see how long the protection of the investigational vaccine against malaria lasts.