ChAd63 and MVA viral vectors encoding the pre-erythrocytic Thrombospondin-Related Adhesion Protein (TRAP) antigen17, fused to a string of multiple CD4+ and CD8+ malaria epitopes (ME)18,19, have been tested in many studies using a standard 8 week prime-boost regime: ChAd63.MVA ME-TRAP. Here, CD4 is linked to malaria.