Heterologous prime-boost vaccination with ChAd63 and MVA expressing the leading pre-erythrocytic antigen, ME-TRAP, is clinically the most potent inducer of CD8+ T cells in humans and the most effective malaria vaccine after RTS,S, demonstrating efficacy (defined as sterile protection or delay) in seven of 15 malaria-naive volunteers (46.7%) after controlled human malaria infection41. This evidence concerns the gene CD8A and malaria.