Interventions for preventing dengue: a mapping review

Dengue remains a pressing global health challenge, particularly in low- and middle-income countries (LMIC). Despite a growing volume of research on prevention strategies, there is a notable lack of consolidated, high-level research capturing the full scope of existing knowledge. The current evidence landscape is fragmented, with studies varying widely in design, focus, and quality. A structured map that includes both primary studies and systematic reviews is urgently needed. Such evidence and gap maps (EGMs) serve as a decision-support tool for funders, policymakers, and researchers by identifying where research exists and where future investments are most needed.

To: 1. comprehensively identify the published literature on dengue prevention strategies; 2. critically appraise systematic reviews; 3. present the findings of objectives 1 and 2 in a single evidence gap map; and 4. identify critical knowledge gaps to inform future primary studies and systematic reviews.

We searched MEDLINE (Ovid), Embase (Ovid), CINAHL (EBSCO), Cochrane Central Register of Controlled Trials (CENTRAL), Cochrane Database of Systematic Reviews (CDSR) in the Cochrane Library, and LILACS (BIREME) on 6 August 2025. We did not apply any date or language restrictions to the searches.

We included randomised controlled trials (RCTs), quasi-randomised trials, non-randomised studies of interventions (NRSIs) and systematic reviews. NRSIs had to have a comparator. We included study designs such as cohort studies, interrupted time series designs, controlled before-after studies, and case-control studies. We did not include case studies or animal studies conducted in a laboratory or semi-field environment. We did not have any restrictions on date or language of publication. We included studies that compared dengue prevention strategies against placebo, no intervention, or usual care. We developed intervention and outcomes categories through a structured stakeholder engagement process and an existing theoretical framework.

We used Cochrane Crowd, Cochrane's citizen science platform designed to host classification tasks, to help identify and describe health-related research. The results collectively identified by the Crowd as being potentially relevant to the EGM were then imported into EPPI Reviewer for further assessment and coding by the author team. Two review authors independently extracted data from the included studies using a structured coding framework developed during the pilot stage. Following coding, we exported data from EPPI Reviewer to EPPI Mapper to generate an interactive, online map that visually displays the distribution of evidence and identifies key gaps by intervention and outcome. We sought to identify evidence and map it, but did not seek to provide a critical appraisal of that evidence. However, to support systematic review teams in understanding where there are evidence synthesis gaps, and to minimise research duplication, we decided to critically appraise the systematic reviews. Two review authors independently appraised the quality of systematic reviews, using A MeaSurement Tool to Assess Systematic Reviews (AMSTAR 2). We partnered with Instituto Veredas, a Brazilian non-governmental organisation, that aims to build bridges between public management, academia, and civil society, to conduct stakeholder engagement.

The searches identified 20,355 records. After deduplication, we screened 16,468 titles and abstracts, then assessed 720 full-text articles for further eligibility. In total, we included 550 studies in the EGM. Evidence from primary studies We included a total of 505 primary studies, comprising 197 RCTs and 308 NRSIs, with 219 published in the past decade. Most studies were conducted at the community level with mixed adult and child populations, predominantly in high-prevalence regions of South America and South Asia. Brazil accounted for the largest share of studies (64 studies), and Aedes aegypti was the most frequently targeted vector species. Of our five main intervention domains (vaccines, environmental, community education, targetting of aquatic stages of the vector and targetting of adult vectors), community education was the most extensively studied (47 RCTs and 140 NRSIs), largely focusing on behavioural and entomological outcomes. These interventions overlapped with vector control interventions targeting both aquatic and adult stages of the mosquito. Evidence from systematic reviews We included 45 systematic reviews. We rated only eight as high or moderate quality using the AMSTAR 2 tool, with the majority classified as low or critically low quality due to methodological weaknesses. Common deficiencies included lack of protocol registration, inadequate justification for study exclusions, and insufficient consideration of risk of bias in interpreting findings. Of the eight high- or moderate-quality reviews, most of which evaluated multiple interventions, two included environmental interventions, three evaluated community education, four assessed vaccines, one evaluated vector control interventions exclusively targeting aquatic stages, and three included vector control of adult mosquitoes. Key gaps For community education, a clear gap exists for implementation outcomes, where the substantial evidence base of 25 primary studies has not been synthesised by any high- or moderate-quality systematic reviews. Adult vector interventions present multiple synthesis gaps despite extensive primary studies, as existing reviews are outdated or restricted to Wolbachia-infected mosquitoes. Aquatic-stage interventions show consistent synthesis gaps across all outcome domains. For vaccines, evidence is particularly limited for implementation outcomes and entirely absent for behavioural outcomes, indicating minimal evidence in these domains. Finally, environmental interventions display synthesis gaps for behavioural and implementation outcomes, where primary studies are available but high- or moderate-quality systematic reviews are lacking.

The primary challenge in the dengue prevention evidence base is not the absence of studies, but the lack of strategic synthesis aligned with decision-making needs. Priority areas for future research include: • updated and comprehensive systematic reviews for adult and aquatic-stage vector interventions; • synthesis of implementation and behavioural evidence across all non-vaccine interventions; and • systematic evaluation of adverse effects beyond vaccine technologies. From a policy perspective, reliance on entomological outcomes alone remains insufficient. Greater emphasis on epidemiological and implementation outcomes is essential to support effective, scalable, and context-sensitive dengue control strategies. Aligning future research agendas with these gaps may substantially enhance the usability of the evidence for public health decision-making, particularly in endemic and resource-constrained settings.

The Cochrane Collaboration funded stakeholder engagement work, information specialist expertise, and some of the authors.

Protocol (2025): DOI: 10.1002/14651858.CD016299.