An alternative to QALYs:saved young life equivalent (SAVE)

EDITOR,-Stephen J Lewis and colleagues neglect the importance of immunity in their analysis of the associations of severe and mild malaria with antimalarial chemoprophylaxis. They state that "Africans living in Africa and those living in the United Kingdom were combined to form one group as they appeared to have the same proportions of severe versus mild malaria." This statement is not compatible with my clinical experience. Immunity rather than drug prophylaxis is the best predictor of whether a patient gets severe or mild malaria, and an individual's previous exposure to malaria is more significant than his or her ethnic group alone. Most textbooks of tropical medicine discuss malaria in immune and non-immune patients in separate sections. It is not valid to combine data from a study of immune and non-immune subjects and draw conclusions about the time to presentation or association with sex or indeed the effect of prophylaxis on the severity of malaria generally. An impressive protective effect of drug prophylaxis was found in the white ethnic group. Because in the African patients there is the confounding factor of acquired immunity the study should have been restricted to the non-immune white group alone. PAUL,ANTHONY REEVE Central Hospital, Private Mail Bag 013, Port Vila, Vanuatu