Autochthonous dengue transmission in Europe: epidemiology, mechanisms, and modelling insights

Dengue is the most rapidly expanding arboviral infection globally, with rising incidence and widening geographic distribution driven by urbanisation, climate change, vector expansion, and global mobility. Although traditionally confined to tropical and subtropical regions, dengue is increasingly emerging in temperate settings, including Europe. Recent outbreaks in Italy, Spain, and France, together with evidence of under-recognised transmission, indicate a transition from sporadic importation to recurrent autochthonous infection. This shift is facilitated by the establishment of Aedes albopictus, increasing climatic suitability, an increase in case importation from endemic areas and delays in clinical recognition and public health response. In non-endemic regions, dengue presents distinct challenges, including low population immunity, limited clinical awareness, and diagnostic constraints that may hinder early detection. While advances in vaccines, particularly TAK-003, and novel vector control strategies such as Wolbachia-based interventions offer new opportunities, their role in Europe remains context-specific and complementary to strengthened surveillance and preparedness systems. Modelling approaches provide valuable decision support but are constrained by data limitations in emerging settings. The emergence of dengue in Europe should be viewed as an early signal of broader changes in vector-borne disease dynamics. Proactive investment in integrated surveillance, diagnostics, vector control, and targeted vaccination strategies will be essential to mitigate future risk and prevent sustained transmission in non-endemic regions. Dengue is the fastest expanding arboviral disease globally, with increasing incidence and geographic spread driven by climate change, urbanisation, and global mobility. Europe is transitioning from a non-endemic setting to one experiencing recurrent autochthonous dengue transmission, with outbreaks reported in Italy, Spain, and France since 2024. The widespread establishment of Aedes albopictus, combined with increasing climatic suitability, is enabling seasonal transmission in temperate regions. In Europe, the main near-term risk is seasonal re-establishment rather than proven viral overwintering, with overwintering mosquito populations and repeated introductions helping to bridge transmission seasons. Dengue emergence in Europe is driven by interacting determinants, including vector expansion, human mobility, urban environments, and gaps in surveillance and response systems. Clinical recognition of dengue in non-endemic settings is often delayed due to non-specific presentation and low awareness, contributing to under-diagnosis and missed opportunities for early intervention. Diagnostic strategies require a time-dependent approach integrating molecular, antigen, and serological testing, as emphasised in recent WHO guidance. Current dengue vaccines, including TAK-003, show promise but have limited applicability in low-transmission settings, where targeted rather than population-wide use is likely. Novel vector control approaches, including Wolbachia-based interventions, offer promising complementary strategies but require further evaluation in temperate settings. Emerging antiviral strategies, such as mosnodenvir, provide early proof-of-concept for dengue prophylaxis and could represent a future adjunct to vaccines and vector control. Integrated, multisectoral preparedness, combining surveillance, diagnostics, vector control, modelling, and targeted vaccination, is essential to prevent sustained dengue transmission in Europe and other non-endemic regions.