Effectiveness and efficacy of long-lasting insecticidal nets for malaria control in Africa: Systematic review and meta-analysis of randomized controlled trials

Background: This systematic review and meta-analysis aims to compare the effectiveness and efficacy of pyriproxyfen, chlorfenapyr, and piperonyl butoxide long-lasting insecticidal nets (LLINs) with pyrethroid-only LLINs for malaria control in Africa, as pyrethroid resistance threatens the effectiveness of these nets in controlling malaria. Method: The protocol was registered in PROSPERO (CRD42024499800). The extracted data from eligible studies were pooled using the random effects model and expressed as a risk ratio (RR) with a 95% confidence interval (CI) by using Excel and STATA 17. Result: A study involving 21,916 households from 11 randomized controlled trials found using chlorfenapyr and piperonyl butoxide LLINs post-intervention for 6 months to 36 months significantly reduced the risk of malaria infection compared to pyrethroid-only nets. The chlorfenapyr treatment group had a 10% reduction in malaria infection risk, with a pooled overall prevalence of 25.96 per 100 children in the chlorfenapyr group and 32.38 per 100 children in the piperonyl butoxide group compared to 41.60 per 100 children in the control Pyrethroid-only group. This meta-analysis determined entomological outcomes effectiveness and efficacy showed they effectively reduced vector density per household per night and mean inoculation rates, with a 23% reduction in chlorfenapyr, a 7% reduction in pyrethroid-only treatments, and a 12% reduction in piperonyl butoxide treatments groups. Conclusion: This study found that chlorfenapyr and piperonyl butoxide treatments significantly reduced malaria infection risk in children in African countries. The review emphasizes the effectiveness of malaria control measures in preventing infection, anaemia, vector density, and inoculation rates. The study found that chlorfenapyr (CFP) long-lasting insecticidal nets (LLINs) are highly effective and superiorly efficacious in reducing malaria infection, case incidence, and anemia among children, as well as reducing mean indoor vector density, mean entomological inoculation rate, and sporozoite rate compared to pyriproxyfen (PPF) long-lasting insecticidal nets (LLINs) in Africa. The study found that chlorfenapyr (CFP) and piperonyl butoxide (PBO) long-lasting insecticidal nets (LLINs) are highly effective and efficacious in reducing malaria infection, case incidence, and anaemia among children, as well as reducing indoor vector density, inoculation rate, and sporozoite rate in Africa as compared to pyrethroid-only LLINs. The evidence generated found that piperonyl butoxide (PBO) long-lasting insecticidal nets effectively and efficaciously reduce indoor vector density, entomological inoculation rate, and sporozoite rate of malaria parasites compared to Pyriproxyfen (PPF) LLINs, but no significant difference was found in malaria infection reduction among children who use piperonyl butoxide (PBO) versus Pyriproxyfen (PPF) long-lasting insecticidal nets in Africa. The study found that chlorfenapyr (CFP) long-lasting insecticidal nets (LLINs) are highly effective and superiorly efficacious in reducing malaria infection, case incidence, and anemia among children, as well as reducing mean indoor vector density, mean entomological inoculation rate, and sporozoite rate compared to pyriproxyfen (PPF) long-lasting insecticidal nets (LLINs) in Africa. Therefore, policymakers and health planners should give a great deal of emphasis on addressing the effectiveness, efficacy, and resistance management of long-lasting insecticidal nets (LLINs) as part of their current public health agenda to eliminate malaria.