Intermittent treatment for malaria and anaemia control at time of routine vaccinations in Tanzanian infants: a randomised, placebo-controlled trial

Clinical malaria and severe anaemia are major causes of paediatric hospital admission and death in many malaria-endemic settings. In the absence of an effective and affordable vaccine, control programmes continue to rely on case management while attempting the large-scale deployment of insecticide-treated nets. We did a randomised, placebo-controlled trial to assess the efficacy and safety of intermittent sulphadoxine-pyrimethamine treatment on the rate of malaria and severe anaemia in infants in a rural area of Tanzania. We randomly assigned 701 children living in Ifakara, southern Tanzania, sulphadoxine-pyrimethamine or placebo at 2, 3, and 9 months of age. All children received iron supplementation between 2 and 6 months of age. The intervention was given alongside routine vaccinations delivered through WHO's Expanded Program on Immunisation (EPI). The primary outcome measures were first or only episode of clinical malaria, and severe anaemia in the period from recruitment to 1 year of age. Morbidity monitoring through a hospital-based passive case-detection system was complemented by cross-sectional surveys at 12 and 18 months of age. Results were expressed in terms of protective efficacy (100 [1-hazard ratio] %) and analysis was by intention to treat. 40 children dropped out (16 died, 11 migrated, 12 parents withdrew consent, and one for other reasons). Intermittent sulphadoxine-pyrimethamine treatment was well tolerated and no drug-attributable adverse events were recorded. During the first year of life, the rate of clinical malaria (events per person-year at risk) was 0·15 in the sulphadoxine-pyrimethamine group versus 0·36 in the placebo group (protective efficacy 59% [95% CI 41–72]), and the rate of severe anaemia was 0·06 in the sulphadoxine-pyrimethamine group versus 0·11 in the placebo group (50% [8–73]). Serological responses to EPI vaccines were not affected by the intervention. This new approach to malaria control reduced the rate of clinical malaria and severe anaemia by delivering an available and affordable drug through the existing EPI system. Data are urgently needed to assess the potential cost-effectiveness of intermittent treatment in areas with different patterns of malaria endemicity.