This vaccine trial supports the safety and tolerability of adenovirus vaccines within the range tested 1×1010–1×1011 pu, and indicates that two antigens may be safely and effectively combined, and the first evidence (see also Tamminga et al) that adenovirus-vectored malaria vaccines induce robust IFN-γ CD8+ T cell responses in humans. This evidence concerns the gene CD8A and malaria.