Impact of Project Wolbachia - Singapore on Dengue Incidence

Not Applicable

Completed

• Conditions: Dengue
• Interventions: Biological: Biological (Male Wolbachia-infected Aedes aegypti)

• Registration Number: NCT05505682
• Lead Sponsor: National Environment Agency, Singapore

Brief Summary

The study is a cluster-randomised controlled trial set in Singapore, to assess if the deployment of male Wolbachia-infected Aedes aegypti mosquitoes can reduce dengue incidence in intervention clusters.

Detailed Description

The study is designed as a parallel, two-arm, non-blinded cluster-randomised controlled trial to be conducted in high-rise public housing estates in Singapore. The aim is to determine whether large-scale deployment of male Wolbachia-infected Ae. aegypti mosquitoes can significantly reduce dengue incidence in intervention clusters. The investigators will use the cluster-randomised design, with the study area comprising 15 clusters with a total area of 10.9 km2, covering approximately 722,000 residents in 1,700 apartment blocks. Eight clusters will be randomly selected to receive the intervention, while the other seven will serve as non-intervention clusters. Intervention efficacy will be estimated through two primary endpoints: (1) odds ratio of Wolbachia exposure distribution (i.e. probability of living in an intervention cluster) among laboratory-confirmed reported dengue cases compared to test-negative controls, and (2) laboratory-confirmed reported dengue counts normalized by population size in intervention versus non-intervention clusters.

Study Timeline

• Study First Submitted: 2022-07-19
• Study Start: 2022-07-28
• Study First Submitted QC: 2022-08-16
• Study First Posted: 2022-08-18
• Primary Completion: 2024-09-13
• Study Completion: 2024-09-13
• Status Verified: 2025-05
• Last Update Submitted: 2025-05-19
• Last Update Posted: 2025-05-22

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 724428

Inclusion Criteria

Not provided

Exclusion Criteria

Not provided

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Intervention clusters	Biological (Male Wolbachia-infected Aedes aegypti)	Residential areas that receive releases of male Wolbachia-infected Aedes aegypti

Primary Outcome Measures

Name	Time	Method
Laboratory-confirmed reported dengue case counts normalized by population size in intervention versus non-intervention clusters	Up to 3 years	Dengue cases data will be obtained from the national surveillance network of diagnostic laboratories which receive samples for dengue testing.
Odds ratio of Wolbachia exposure distribution among laboratory-confirmed reported dengue cases compared to test-negative controls	Up to 3 years	Dengue cases and dengue test-negative controls data will be obtained from the national surveillance network of diagnostic laboratories which receive samples for dengue testing.

Secondary Outcome Measures

Name	Time	Method
Prevalence of Ae. aegypti/Ae. albopictus mosquitoes	Up to 3 years	Data will be obtained from the national gravitrap surveillance system
Public Attitudes, Perceptions & Knowledge (APK) of Wolbachia and other vector control interventions	Up to 3 years	Sentiment surveys pre-trial and during the course of the trial, using true/false and Likert-type scales. Higher scores mean better outcomes.

Trial Locations

Locations (1)

National Environment Agency; 🇸🇬 Singapore, Singapore