Operationalized releases of wAlbB Wolbachia in Aedes aegypti lead to sharp decreases in dengue incidence dependent on Wolbachia frequency

In Aedes aegypti mosquitoes, introduction of certain strains of inherited Wolbachia symbionts results in transmission blocking of various viruses of public health importance, including dengue. This has resulted in a 'replacement' strategy for dengue control involving release of male and female mosquitoes, whereupon Wolbachia is able to spread through Ae. aegypti populations to high frequency and reduces the incidence of dengue. Wolbachia strain wAlbB is an effective transmission blocker and stable at high temperatures, making it very suitable for use in hot tropical climates. Following the first trial field releases of the wAlbB strain in Ae. aegypti in Malaysia, releases of wAlbB Ae. aegypti have for the first time become operationalized by the Malaysian health authorities. We report here on changes in dengue incidence based on a set of 20 releases sites and 76 control sites in high rise residential areas, which allows us to directly assess the impact of Wolbachia frequency on dengue incidence. The results indicate an average reduction in dengue of 62.4% (confidence intervals 50-71%); importantly the level of suppression increased with Wolbachia frequency, with suppression of 75.8% (confidence intervals 61-87%) estimated at 100% Wolbachia frequency. These findings emphasize the large impacts of wAlbB Wolbachia invasions on dengue incidence in an operational setting, with the expectation that the level of dengue will further decrease as wider areas are invaded. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement Funding for the study was provided by Wellcome Trust Awards 226166, 108508, 202888 and Ministry of Health Malaysia NMRR-16-297-28898. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Medical Research and Ethics Committee (MREC), Ministry of Health Malaysia gave ethical approval for this work. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors