A strain theory of malaria transmission.

Does the fact that the risk o f getting malaria is high in most endemic areas mean that it will be impossible to control through vaccination? Not if malaria is composed of several mildly transmissible strains, and what we are measuring as the high risk is the probability of being infected by any one of the several strains circulating independently within the same area. In this article, Sunetra Gupta and Karen Day discuss a strain theory of malaria transmission that fits both recent serological and molecular observations and more conventional epidemiological data on age distributions of infection and disease. Their analyses suggest that the transmissibility of malaria has been grossly overestimated, and that the control of malaria through vaccination may be far easier than previously assumed.