Efficacy of Spatial Repellents in Malaria Prevention: A Meta-Analysis of Randomized Controlled Trials

The efficacy of spatial repellents in preventing malaria infections is unclear. In the present study, a meta-analysis of four randomized controlled trials conducted in China, Indonesia, and Kenya, involving 6,745 participants, was conducted to assess the efficacy of spatial repellents in reducing malaria infections. The risk of malaria infection was lower with the use of spatial repellents (681 [20.0%] of 3,399 participants) compared with controls (1,055 [31.0%] of 3,346 participants), resulting in a 52% risk reduction (pooled risk ratio: 0.48; 95% CI: 0.33 to 0.70; P <0.001). No statistically significant effects on mosquito density (mean difference -10.0; 95% CI: -29.6 to 9.7), measured via human landing catch, or sporozoite rates (82 [0.007%] of 12,321 mosquitoes versus 79 [0.006%] of 14,151 mosquitoes; risk ratio: 1.13; 95% CI: 0.83 to 1.54) were observed. High statistical and methodological heterogeneity limited the certainty of pooled estimates. In this meta-analysis, spatial repellents were associated with a substantial reduction in malaria infections, supporting their role as a complementary intervention for malaria prevention.