Efficacy of PermaNet Dual compared to Interceptor G2 and PermaNet 3.0 in experimental huts in Siaya County, western Kenya.

Background: Pyrethroid-chlorfenapyr nets have shown significant epidemiological impact over pyrethroid-only and pyrethroid plus piperonyl-butoxide (PBO) in Africa. A non-inferiority evaluation of PermaNet Dual, a new chlorfenapyr plus deltamethrin net, compared to Interceptor G2, was conducted in experimental huts in Siaya, Kenya against free-flying pyrethroid-resistant Anopheles funestus.

Methods: This study was an experimental hut trial, following a 7 by 7 Latin Square design. Seven treatments and seven sleepers were deployed in the experimental huts daily and rotated weekly and daily, respectively. Mosquitoes were collected every morning between 06:30 h and 08:30 h and were assessed for blood feeding and then monitored for immediate knockdown 1-h post collection and delayed mortality after 72 h. Differences in proportional outcomes were analysed using the blocked logistic regression model, while differences in numerical outcomes were analysed using the negative binomial regression model. Non-inferiority determination was performed based on World Health Organization (WHO) protocol.

Results: Mortality at 72 h was 30.2% for PermaNet 3.0, 44.4% for the Interceptor G2 and 49.2% for the PermaNet Dual. Blood feeding was highest with PermaNet Dual at 15%, and least with PermaNet 3.0 at 10%. PermaNet Dual and Interceptor G2 had no significant differences in mortality (OR = 1.10, 95% CI 1.00-1.20) or blood feeding (OR = 1.18, 95% CI 1.04-1.33) and the lower confidence bounds were within the non-inferiority margins but for blood feeding, non-inferiority was relatively high to the upper 95% confidence bound. PermaNet Dual was non-inferior to the Interceptor G2 and superior to the PermaNet 3.0 nets in causing mortality but inferior to PermaNet 3.0 in blood feeding inhibition of the vectors.

Conclusion: PermaNet Dual met the WHO criteria for non-inferiority to Interceptor G2 and may be considered for deployment for public health use against pyrethroid-resistant Anopheles vectors of malaria.