Malaria vaccine development.

Prospects for the development of effective malaria vaccines have greatly improved over the last 15 years. For further progress to be achieved rapidly, the need for clinical research centres, where exposure and re-exposure to infection can be carefully controlled, is paramount. At such centres, it is possible to evaluate the safety and efficacy of vaccine preparations, using different strams and species of parasite, and to undertake studies in both nonimmune and partially immune volunteers. However, as efficacy under these conditions may not be a good indicator of efficacy under other conditions, the results of such studies should be complemented by field trials in endemic areas. It seems probable that vaccines may show degrees of partial effectiveness in relation to different strains, species, intensities of parasite inocula, and hosts.