MALOPRIM(R) MALARIA PROPHYLAXIS IN CHILDREN LIVING IN A HOLOENDEMIC VILLAGE IN NORTH-EASTERN TANZANIA

A randomized, double-'blind', placebo-controlled trial of weekly Malop rim(R) (dapsone-pyrimethamine, D-P) for malaria prophylaxis was conduc ted at Magoda village in north-eastern Tanzania. The effect of D-P on the incidence of clinical malaria, Plasmodium falciparum prevalence an d density, splenomegaly, and packed cell volume (PCV) was investigated in a cohort of 249 children (126 receiving D-P and 123 receiving plac ebo) aged 1-9 years. The case definition of clinical malaria (malaria fever) was measured axillary temperature greater than or equal to 37.5 degrees C and/or reported fever, and P. falciparum asexual parasitaem ia greater than or equal to 5000/mu L. Children aged 1-4 years given D -P experienced 1.56 episodes of clinical malaria per year, whereas chi ldren on placebo experienced 2.55 episodes (relative rate [RR]=0.61, 9 5% confidence interval [CI] 0.47, 0.80). Thus, D-P protective efficacy against clinical malaria, in this age group, was 39% (95% CI 20%, 53% : P=0.0002). The annual incidence of clinical malaria among children a ged 5-9 years was 0.16 episodes in the D-P group and 0.26 episodes in those receiving placebo (RR=0.58, 95% CI 0.26, 1.28; P=0.17). Increase d malaria transmission and drug resistance, during the course of the t rial, resulted in a reduction in the protective efficacy of D-P. Overa ll, D-P was able to reduce parasite densities and splenomegaly. D-P pr ophylaxis also resulted in an increase in PCV but this effect diminish ed towards the end of the trial. D-P exerted a suppressive effect on a sexual parasitaemia throughout the trial.