Spatio-temporal clustering of dengue in Valle del Cauca, Colombia

Background Dengue is endemic in Colombia's Valle del Cauca region. The precise timing and spatial scale of seasonal dengue transmission necessary for effective reactive interventions at the sub-municipal level across the 42 municipalities of Valle del Cauca remain unclear. This study aimed to identify spatio-temporal dengue clusters in Valle del Cauca. Methodology/Principal Findings A retrospective observational study was conducted using individual laboratory-confirmed dengue cases, including residential geolocation and consultation dates, reported by healthcare providers to the Sistema Nacional de Vigilancia en Salud Pública (SIVIGILA) in 2022. Residence was utilized as the probable site of infection. Spatio-temporal clustering was analyzed using Kulldorff's space-time scan statistic to identify statistically significant dengue clusters. Results were mapped using R. As a second aim, the association between clinical and demographic characteristics and dengue hospitalization was evaluated. Of 3,964 dengue cases reported in Valle del Cauca in 2022, 2,232 (56%) were laboratory-confirmed. Of these, 1,973 occurred in the defined areas of the nine municipalities included in the spatio-temporal analysis of this study. We identified 28 clusters at the sub-municipal level, with radii of 0–0.98 km, lasting 1–6 months and containing 10–114 cases. Twenty-six clusters (92.9%) spanned both warm–dry and cool–wet seasons, and clusters accounted for 32.0% of spatially analyzed cases. 960 patients were hospitalized. Lower socioeconomic status (OR 1.30, 95% CI 1.07–1.57), enrollment in the state-subsidized insurance scheme (OR 1.74, 95% CI 1.41–2.15) compared with the contributory scheme, and age ≥ 70 years compared to ages 20–29 years (OR 2.47, 95% CI 1.51–4.04) were associated with higher odds of hospitalization. Conclusions/Significance This study identified dengue clusters at the sub-municipal level with the potential to inform reactive dengue control interventions and demonstrated a disproportionate impact on socioeconomically disadvantaged populations and the elderly in Valle del Cauca, Colombia.