Chlorfenapyr-pyrethroid nets for pyrethroid-resistant malaria vectors: efficacy, resistance risks, and policy implications.

In 30 seconds

This systematic review assessed the efficacy, resistance risks and policy implications of chlorfenapyr-pyrethroid insecticide-treated nets for pyrethroid-resistant malaria vectors. It included 31 studies identified from literature published between 2010 and 2024. Compared with pyrethroid-only nets, combination nets produced a 1.8-fold increase in mosquito mortality (95% CI: 1.5-2.1). Community trials reported 40-60% reductions in malaria infection incidence and entomological inoculation rates after deployment. The review also identified early chlorfenapyr resistance signals in Anopheles gambiae in Central Africa, underscoring the need to monitor resistance as these nets are used.

Key findings

• Combination nets produced a 1.8-fold increase in mosquito mortality versus pyrethroid-only nets (95% CI: 1.5-2.1).
• Community trials reported 40-60% reductions in malaria infection incidence and entomological inoculation rates following deployment.
• In Central African Anopheles gambiae, chlorfenapyr resistance was reported (RR: 2.4, p = 0.01) and linked to CYP6P4 metabolic overexpression.
• Agricultural pesticide use correlated with vector resistance patterns (r = 0.62, p < 0.05).

Why it matters

The review brings together evidence that combination nets can improve vector control where pyrethroid resistance threatens malaria prevention, while highlighting that resistance to chlorfenapyr may also emerge. This balance matters for sustaining the effectiveness of a key intervention: monitoring vector susceptibility and considering insecticide use across public health and agriculture may help preserve gains in malaria control.

What to keep in mind

The review synthesizes heterogeneous evidence, including community trial findings and resistance observations; the abstract does not report pooled clinical effect estimates or study-level quality assessments.