Wolbachia releases for dengue control: why the evidence supports a pause and independent re-evaluation.

BACKGROUND

Aedes aegypti is the primary vector of dengue and other arboviruses whose global incidence continues to rise. In response, releases of Aedes aegypti infected with the wMel strain of Wolbachia pipientis have been promoted as a sustainable, transmission-blocking strategy to curb arboviral disease.

OBJECTIVES

This study was undertaken to reassess the real-world performance of wMel-Wolbachia interventions, evaluate their epidemiological impact and durability under diverse field conditions.

METHODS

Evidence from peer-reviewed publications, program documentation, and routine surveillance systems in countries with large-scale Wolbachia deployments, including Brazil, Colombia, Vietnam, and Indonesia, was synthesised. Temporal patterns of dengue incidence, Wolbachia infection frequencies in mosquito populations, and contextual environmental and operational factors were examined using national and municipal datasets and official reports.

RESULTS

Across settings, wMel-Wolbachia releases have been associated with highly variable epidemiological outcomes, including areas where substantial dengue transmission has persisted or re-emerged after deployment. Field data have documented loss or marked decline of Wolbachia infection in local Aedes aegypti populations and dengue outbreaks within release zones. Limited access to underlying data is available for independent analyses. Theoretical and empirical evidence from vector-pathogen systems indicates that partial transmission blocking potentially imposes selection favouring more transmissible or virulent viral variants.

CONCLUSION

Available evidence does not support unqualified scale-up of wMel-Wolbachia releases as a robust, long-term dengue control strategy across diverse ecological and operational contexts. A global pause on ongoing and planned deployments, alongside an independent, transparent, science-based re-evaluation of effectiveness, safety, and sustainability, is therefore warranted before further expansion.