Long‐term effects of malaria prevention with insecticide‐treated mosquito nets on morbidity and mortality in African children: randomised controlled trial

Abstract

Objective The objective is to investigate the effect of malaria control with insecticide‐treated mosquito nets (ITNs) regarding possible higher mortality in children protected during early infancy, due to interference with immunity development, and to assess long‐term effects on malaria prevalence and morbidity. Methods Between 2000 and 2002, a birth cohort was enrolled in 41 villages of a malaria holoendemic area in north‐western Burkina Faso. All neonates (n = 3387) were individually randomised to ITN protection from birth (group A) vs. ITN protection from age 6 months (group B). Primary outcome was all‐cause mortality. In 2009, a survey took place in six sentinel villages, and in 2010, a census was conducted in all study villages. Results After a median follow‐up time of 8.3 years, 443/3387 (13.1%) children had migrated out of the area and 484/2944 (16.4%) had died, mostly at home. Long‐term compliance with ITN protection was good. There were no differences in mortality between study groups (248 deaths in group A, 236 deaths in group B; rate ratio 1.05, 95% CI: 0.889–1.237, P = 0.574). The survey conducted briefly after the rainy season in 2009 showed that more than 80% of study children carried asexual malaria parasites and up to 20% had clinical malaria. Conclusion Insecticide‐treated mosquito net protection in early infancy is not a risk factor for mortality. Individual ITN protection does not sufficiently reduce malaria prevalence in high‐transmission areas. Achieving universal ITN coverage remains a major challenge for malaria prevention in Africa.