A reduced risk of infection with Plasmodium vivax and clinical protection against malaria are associated with antibodies against the N terminus but not the C terminus of merozoite surface protein 1.

Progress towards the development of a malaria vaccine against Plasmodium vivax, the most widely distributed human malaria parasite, will require a better understanding of the immune responses that confer clinical protection to patients in regions where malaria is endemic. The occurrence of clinical protection in P. vivax malaria in Brazil was first reported among residents of the riverine community of Portuchuelo, in Rondônia, western Amazon.