Global dengue update

Overview

Data as of the end of August 2026

Dengue virus is transmitted mainly through Aedes aegypti and Aedes albopictus mosquitoes, which thrive in tropical and sub tropical urban areas. Key drivers of dengue transmission include rapid urbanization and climate change, both of which are resulting in an increase in permissive environments for mosquitoes, as well as expanded global travel and trade, moving the virus, mosquitoes and infected humans across borders. Circulation of multiple dengue serotypes also raises the risk of severe disease due to secondary infections with a different serotype.

WHO has been monitoring dengue incidence since1954, withMemberStatesreporting cases and deaths to WHOonanannual basis. In response to the changes in the abovementioned drivers of transmission, and the need to better understand changes in intra-annual trends and seasonality patterns, WHO established an almost real-time global surveillance system for dengue in 2024. Currently, this includes monthly data from 185 countries, territories and areas, presented in the global dashboard. This tool also brings together other relevant information for interpreting the global situation such as genomic data available through GenBank, modelled estimates of risk and visualizations of seasonality patterns.

Between January and August2026, 2.2 million cases and over 1100 deaths were reported from 97 countries, territories and areas (Figure 2). The transmission levels to date in 2026 have been the lowest reported since the global surveillance commenced in 2024, with 12.7 million cases and 4.4 million cases reported by the end of August in 2024 and 2025 respectively.