Protection Against Malaria by Intravenous Immunization with a Nonreplicating Sporozoite Vaccine

Each year, hundreds of millions of people are infected with Plasmodium falciparum , the mosquito-borne parasite that causes malaria. A preventative vaccine is greatly needed. Seder et al. (p. [1359][1], published online 8 August; see the Perspective by [Good][2] ) now report the results from a phase I clinical trial where subjects were immunized intravenously with a whole, attenuated sporozoite vaccine. Three of 9 subjects who received four doses and zero of 6 subjects who received five doses of the vaccine went on to develop malaria after controlled malaria infection. Both antibody titers and cellular immune responses correlated positively with the dose of vaccine received, suggesting that both arms of the adaptive immune response may have participated in the observed protection. [1]: /lookup/doi/10.1126/science.1241800 [2]: /lookup/doi/10.1126/science.1244157