Impact of insecticide-treated nets on malaria morbidity and mortality: a systematic review and meta-analysis of randomized controlled trials

Introduction This systematic review and meta-analysis examined the efficacy of insecticide-treated nets (ITNs) in reducing malaria incidence and malaria-related mortality among vulnerable populations.Methodology A comprehensive search of Scopus, Medline, and CINAHL (up-to-April 2, 2026) identified experimental studies (randomised and cluster-randomised trials) evaluating the effect of ITNs impact for malaria control, and the protocol was registered in PROSPERO (CRD42024609183). Pooled-effect-sizes [rate-ratios(RRs) and odds-ratios (ORs)] were calculated, and meta-regression was conducted to examine study-level sources of variation in effect estimates.Results A total of 25 studies were included in the meta-analysis, including 19 assessing malaria-incidence and 6 evaluating malaria-related mortality. Overall, ITNs demonstrated strong protective effects across diverse populations. The pooled-estimate using a random-effects model showed a 29% reduction in malaria incidence among ITNs users in Africa (RR = 0.71; 95% CI: 0.54–0.93; p = 0.0133; I2 = 64%) and 68% in Asia (RR = 0.32; 95% CI: 0.17–0.62; p = 0.0007; I2 = 89.0%). The pooled-odds-ratio for malaria incidence in African studies indicated a 40% reduction in odds (OR = 0.60; 95% CI: 0.44–0.82; p = 0.0011; I2 = 86.2%), whereas the pooled-rate-ratio for malaria-related-mortality in Asia was 0.82 (95% CI: 0.77–0.89; p < 0.0001; I2 = 0) from 5 studies, indicating an 18% reduction in mortality. Meta-regression on 17 studies confirmed an overall significant protective effect of ITNs against malaria(β = −0.84; 95% CI: −1.68 to −0.01; p = 0.05).Conclusion ITNs reduce malaria transmission, though effectiveness varies across regions due to ecological, epidemiological, and implementation differences.