Transmission acceleration outperforms the endemic-channel threshold for dengue outbreak detection

Extreme weather drives dengue transmission beyond historical spatial and temporal incidence patterns. No operational dengue outbreak threshold has been validated for early warning under extreme weather conditions. Here we show that transmission acceleration provides earlier and more consistent outbreak detection than the endemic-channel threshold. We evaluated detectors across a hyperendemic city, seventeen tropical regions, and eight dengue-endemic countries. Acceleration-based detectors consistently outperformed the endemic channel in burden captured, lead time, warning persistence, and sensitivity. At city scale, transmission acceleration captured 4,257 cases per season versus 1,119. It achieved 100% sensitivity versus 30% while triggering within the four-to-eight-week anticipatory window under 6.9 versus 1.6 weeks lead time. These establish acceleration-based detectors as a robust signal for dengue anticipatory action, making them better suited to a transmission landscape increasingly shaped by extreme weather conditions.