Understanding dengue dynamics: spatiotemporal evidence of control failure, inequalities, and the role of climate factors

<title>Abstract</title> <p>Background Dengue remains a pressing public health issue in Brazil, where vector control strategies often suffer from limited effectiveness and sustainability. Although the Brazilian National Dengue Control Program (PNCD) operates with standardized guidelines, few studies have evaluated its long-term effectiveness at the local level, with a consistent dengue transmission history and structured intervention efforts under the PNCD. Moreover, previous research at aggregated scales has shown conflicting associations between socioeconomic development and dengue incidence, highlighting the need for small-area spatiotemporal analyses. Methods We conducted a Bayesian spatiotemporal analysis using Integrated Nested Laplace Approximation (INLA) to assess quarterly dengue incidence in São José do Rio Preto (SJRP), Brazil, from 2012–2024. The model incorporated environmental, entomological, and socioeconomic covariates from census tracts. Results The findings revealed that vector control actions were predominantly reactive and intensified after case surges. Increased literacy rates were associated with a decreased dengue incidence rate, whereas higher relative deprivation increased the risk. These results differ from those of regional studies that associate higher socioeconomic development with an increased dengue burden, emphasizing the value of small-scale analysis to uncover local vulnerabilities. Climatic variables had nonlinear effects, with elevated temperatures and rainfall associated with increased risk. Spatial risk patterns varied significantly over time, with no consistent high-risk clusters. Given the standardized implementation of the PNCD, the SJRP serves as a suitable proxy for assessing the program’s broader effectiveness across Brazil. Conclusion This study underscores the limitations of reactive dengue control strategies and the need for more proactive, integrated, and socially contextualized approaches to address this issue. Small-area analyses provide critical insights into the heterogeneous dynamics of disease transmission and social vulnerability. Expanding the use of innovative tools, such as Wolbachia-based control and sterile insects, among others, may strengthen long-term prevention and guide the development of more resilient national policies.</p>