Malaria vaccines: a toy for travelers or a tool for eradication?

The demonstration of efficacy of two candidate malaria vaccines in children living in malaria-endemic areas, namely RTS,S from the circumsporozoite protein that reduced infection and clinical malaria in Mozambique, and an asexual blood-stage vaccine combining MSP1/MSP2/RESA that reduced parasite density in Papua New Guinea, allows one to believe that a malaria vaccine will be available for the fight against malaria in the next decade. Even if long-lasting impregnated bednets and indoor residual spraying have proven to be effective in reducing malaria transmission, these interventions may not be sufficient in the long-run since they rely on too few compounds and are, thus, vulnerable to the emergence of resistance. New tools, such as malaria vaccines, may, therefore, provide an added value to achieve the goal of local elimination and subsequent eradication of malaria. A promising candidate for that purpose would be a highly efficacious multicomponent vaccine that includes at least a sexual-stage antigen, the appropriate initial setting would be an area with low endemicity and limited population exchange, and the most suitable mode of delivery would be mass vaccination. For nonimmune populations, such as travelers visiting malaria-endemic areas, the usefulness of the first generation of malaria vaccine(s) will be limited, since the level of protection that is foreseen is unlikely to achieve that of malaria chemoprophylaxis. Only long-term travelers, expatriates and soldiers might realistically benefit from a pre-erythrocytic and/or blood-stage vaccine with an intermediate level of efficacy.