FIELD TRIALS OF MALARIA VACCINES

Malaria due to Plasmodium falciparum is probably the most important in fectious disease in the tropical world. About 2000 million people live in areas exposed to malaria and 300 million individuals are infected every year. In Africa south of the Sahara alone, over 1 million childr en die annually as a result of malaria. It is a difficult parasitic di sease both to diagnose and control. It does not provide sterile immuni ty even after long exposure periods. However, acquisition of partial i mmunity allows over 60 per cent of individuals with long exposure to c arry the parasite in their blood without symptoms, posing difficulties for case definition, malaria attributable morbidity and deaths. Furth er, it is extremely difficult to establish the extent to which malaria has influence over the adverse outcome of other infectious disease li ke measles and malnutrition. The complex life cycle of the parasite in volving human and vector mosquitos as well as its allelic diversity an d antigenic variations makes the development and implementation of eff ective malaria control intervention problematic. It is now becoming ev ident that multi-intervention approach may be the most appropriate way of combating malaria in view of the increasing resistance of the para site to antimalarial drugs as well as vector mosquitoes to insecticide s. Malaria vaccines will therefore play a major role in future malaria interventions. New malaria vaccine candidates will require testing in malaria endemic countries. Sufficient sites for testing potential mal aria vaccines must be prepared. In this paper we discuss the necessary preparations required for field testing of malaria vaccines in tropic al countries.