A quantitative approach to recommendations on malaria prophylaxis.

In order to develop recommendations for malaria prophylaxis, a quantitative method is needed to balance the risk of Plasmodium falciparum malaria infections against the toxicity of antimalarial drugs. Using decision analysis, we estimated the expected mortality associated with three alternative regimens of prophylactic drugs for visitors to three areas with different risks of infection with chloroquine-resistant P. falciparum. The model used took into account the risks of malaria and of adverse reactions to antimalarial drugs. Estimates of the parameters used in the analysis were based on observations made on U.S. travellers. Reducing the risk of malaria infection was found to have a far greater impact on lowering the expected mortality than that of increasing the chemoprophylactic efficacy of the drugs used, thereby emphasizing the need for travellers to use anti-mosquito measures in malarious areas. The analytical method described can be used to define optimal malaria prevention strategies.