Attractive targeted sugar baits (ATSBs) are a novel malaria control tool designed to target mosquitoes outdoors. We conducted a cluster-randomised trial to evaluate the impact of ATSBs on malaria indicators in Kenya. Seventy clusters (>100 households/cluster) in Siaya county were randomly assigned (1:1) to intervention or control. Pyrethroid-only long-lasting insecticidal nets were distributed to all clusters, aiming for universal coverage. Two ATSBs containing dinotefuran were hung outside household structures in intervention clusters. ATSBs were monitored every two months and replaced every six months over two years. Three consecutive cohorts of randomly selected children (1-<15 years) were enrolled, aiming to accrue 1,260 person-years over two years of follow-up. Incidence of clinical malaria (fever with a positive malaria test) was the primary outcome. A multilevel Poisson regression model was applied, with clusters as a random intercept and study arm as a fixed effect. Secondary outcomes were malaria prevalence in community residents (≥1 month), and parity of mosquitos captured through human landing catches. In March 2022, ATSBs were delivered to 33,180 of 33,419 (99.3%) household structures in intervention clusters. Overall, 268,268 ATSBs were deployed over two years. Of 2,962 cohort children enrolled (intervention=1,497; control=1,465), 2,869 (96.9%) were included in the primary analysis (intervention=1,461; control=1,408), contributing 1,445 person-years of follow-up. Malaria incidence was 1.32 episodes per person-years in the intervention arm versus 1.20 in the control (unadjusted incidence rate ratio 1.11; 95% CI: 0.75-1.65; p=0.598). Of 7,488 community residents surveyed (intervention=3,760; control=3,728), 1,474 (39.2%) intervention and 1,461 (39.2%) control participants tested positive for malaria (unadjusted odds ratio [OR] 0.98; 95% CI: 0.60-1.59; p=0.93). Of 6,457 female anopheles mosquitoes collected (intervention=4,058; control=2,399), 3,579 (88.2%) intervention and 1,973 (82.2%) control mosquitoes were parous (OR 1.34; 95% CI: 0.91-1.99; p=0.14). In Kenya, we found no evidence that ATSBs reduced clinical malaria incidence, malaria prevalence, or vector parity.

The authors have declared no competing interest.

NCT05219565

This work was funded by Integrated Vector Control Consortium (IVCC), UK, through support from the Bill & Melinda Gates Foundation (grant: INV-007509), the Swiss Agency for Development and Cooperation (SDC) (grant: 81067480) and UK Aid (grant: 30041-105). The findings and conclusions contained within are those of the authors and do not necessarily reflect positions or policies of the Bill & Melinda Gates Foundation, SDC or UK Aid. The authors who received the award for this trial are FK, AS and EO. The ATSB study multi-country consortium, including researchers and technical advisors from IVCC (the funder), designed the trial and aligned it across the three countries IVCC had no role in data collection, analysis, or interpretation, or writing of the report. The URLs to the sponsors websites are: https://www.ivcc.com/ https://www.gatesfoundation.org/ https://www.eda.admin.ch/eda/en/fdfa/fdfa/organisation-fdfa/directorates-divisions/sdc.html https://www.ukaiddirect.org/

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Kenya Medical Research Institute Scientific and Ethics Review Unit Liverpool School of Tropical Medicine Research Ethics Committee A reliance agreement based on Kenya Medical Research Institute Scientific and Ethics Review Unit review was submitted to the Centers for Disease Control and Prevention Institutional Review Board.

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