In this study, we have demonstrated that the IL-15 containing MVA-CSP vaccine induces substantially higher levels of anti-CSP IgG antibody and most importantly, vaccinated mice had a reduced parasite burden through the course of infection and reached significantly lower peak parasitemia and had an accelerated parasite clearance against a sporozoite challenge than a similar MVA-CSP construct which did not express IL-15. This evidence concerns the gene IL15 and infection.