WHO update on the assessment of Wolbachia population replacement for the control of Aedes-borne diseases

WHO is undertaking an updated review of Wolbachia population replacement and remains committed to providing Member States with evidence-based guidance on its use. This work will include a new systematic review incorporating the full body of evidence on the epidemiological impact of Wolbachia population replacement, including studies published since the original evidence assessment. The systematic review will also address the population suppression approach, which may also be achieved using Wolbachia, and will synthesize and assess evidence on contextual factors relevant to country decision-making, consistent with WHO guideline development processes. Alongside this, WHO is developing an operational manual for the population replacement approach, to guide country preparation and implementation of the intervention, as appropriate.

The updated body of evidence will be considered by WHO's new integrated vector control Guideline Development Group (GDG), which is expected to convene in the first quarter of 2027. Following evidence appraisal, recommendation formulation, and the completion of WHO's established review and approval processes, publication of recommendations, as appropriate, is anticipated in late 2027, with finalization and publication of the operational manual to follow, dependent on the GDG outcomes.

Wolbachia is a naturally occurring intracellular bacterium that can be introduced into Aedes mosquito populations, with the aim of reducing the mosquitoes' ability to transmit viral infections such as dengue virus. In 2020, the WHO Vector Control Advisory Group (VCAG) reviewed evidence from field trials on the population replacement approach, conducted in multiple countries, and concluded that the intervention had demonstrated epidemiological impact. VCAG subsequently advised WHO to initiate the guideline-development process to inform future recommendations. Since that time, the evidence base has continued to expand, with additional results becoming available from a broad range of study types and a growing number of implementation settings. WHO recognizes that several countries and partners are already implementing or evaluating Wolbachia population replacement approaches and that there is considerable interest in the development of an evidence-based WHO recommendation for this intervention.