Reducing long-term disease burden while strengthening public health systems 

Dengue and other mosquito-borne diseases are increasing as climate change expands mosquito habitats and intensifies outbreaks. Children and low-income households are disproportionately affected, placing sustained pressure on already stretched health systems. 

Despite decades of effort, most responses remain reactive. Spraying and outbreak control are costly, short-lived and often arrive too late. Many countries remain locked in cycles of emergency response rather than durable prevention. 

The solution: prevention embedded into public health systems 

The World Mosquito Program’s Wolbachia method offers a fundamentally different approach. By introducing the naturally occurring bacterium Wolbachia into Aedes aegypti mosquitoes, their ability to transmit dengue, Zika, chikungunya and yellow fever is significantly reduced. 

The method does not involve genetic modification and once established at high levels is designed to be self-sustaining. This provides long-term protection without the need for continuous releases, repeated spraying or ongoing behaviour-change campaigns. 

The approach is designed to be embedded within routine public health systems. Following successful implementation in Vietnam and Timor-Leste, the partnership is scaling into Sri Lanka. 

Why this is a Big Bet worth backing 

The Wolbachia method represents a rare prevention solution that is scientifically proven, publicly accepted and designed to last. Once established, it delivers population-wide protection and reduces reliance on repeated, high-cost interventions. 

Globally, treated areas have seen significant reductions in dengue incidence and hospitalisations compared to untreated communities. In southern Vietnam and Timor-Leste, more than 500,000 people have been protected, with large-scale community engagement and health worker training building strong public trust and acceptance. 

This is not short-term outbreak control. It is a foundational shift toward long-term national prevention and more resilient public health systems. 

The opportunity 

Investment at this stage supports the efficient scaling of the Wolbachia method into countries and regions facing rising climate-driven disease risk. Funding helps consolidate national adoption, strengthen long-term quality assurance, and extend protection to communities most exposed to future outbreaks. 

The focus is on embedding prevention within routine public health systems so protection can be maintained and expanded over time, moving countries away from cyclical response and toward sustained disease control. 

Long-term prevention. Stronger health systems. Protection that endures.