Protective efficacy of interventions for preventing malaria mortality in children in Plasmodium falciparum endemic areas

BACKGROUND Insecticide-treated mosquito nets (ITNs) and indoor-residual spraying (IRS) are recommended strategies for preventing malaria in children. While their impact on all-cause child mortality is well documented, their impact on reducing malaria-attributable mortality has not been quantified. While the impact of intermittent preventive therapy in pregnant women (IPTp) and ITNs in pregnancy for improving birth outcomes is also well established, their impact on preventing neonatal or child mortality has not been quantified. METHODS We performed two systematic literature reviews in Plasmodium falciparum endemic settings; one to estimate the effect of ITNs and IRS on preventing malaria-attributable mortality in children 1-59 months, and another to estimate the effect of ITNs and IPTp on preventing neonatal and child mortality through improvements in birth outcomes. RESULTS We estimate the protective efficacy (PE) of ITNs and IRS on reducing malaria-attributable mortality 1-59 months to be 55%, with a range of 49-61%, in P. falciparum settings. We estimate malaria prevention interventions in pregnancy (IPTp and ITNs) to have a pooled PE of 35% (95% confidence interval: 23-45%) on reducing the prevalence of low birth weight (LBW) in the first or second pregnancy in areas of stable P. falciparum transmission. CONCLUSION This systematic review quantifies the PE of ITNs for reducing malaria-attributable mortality in children, and the PE of IPTp and ITNs during pregnancy for reducing LBW. It is assumed the impact of IRS is equal to that of ITNs on reducing malaria-attributable mortality in children. These data will be used in the Lives Saved Tool (LiST) model for estimating the impact of malaria prevention interventions. These data support the continued scale-up of these malaria prevention interventions in endemic settings that will prevent a considerable number of child deaths due directly and indirectly to malaria.