Project Wolbachia at ten

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    Ten years of releasing mosquitoes on purpose.

    On 18 October 2016, Singapore’s National Environment Agency released about 3,000 male mosquitoes carrying Wolbachia at Braddell Heights. This doodle follows the decade that turned that first release into a national programme, using only published numbers.

    The decade, in text

    1. 2016
      Day one.On 18 October, NEA’s Environmental Health Institute releases about 3,000 males at Braddell Heights.Coverage: 4,200 households across three study sites. Mosquitoes: about 3,000 on day one. Source: NEA, 18 Oct 2016.
    2. 2017
      Half isn’t enough.Phase 1 halves mosquito numbers. But mosquitoes from next door move in, and a few females slip through sorting.Coverage: 3 study sites, not counted in households. Mosquitoes: no published weekly total found. Source: NEA, Phase 1 results.
    3. 2018
      New partner.Phase 2 begins in April. In September, Verily’s Debug team joins as a collaborator.Coverage: 2 Phase 2 study sites. Mosquitoes: no published weekly total found. Sources: NEA, 18 Sep 2018; MSE, 2022.
    4. 2019
      Past 90%.Phase 3 cuts the urban Aedes aegypti population by more than 90% across 144 residential blocks.Coverage: 144 residential blocks in Phase 3. Mosquitoes: no published weekly total found. Source: NEA, 7 Oct 2019.
    5. 2020
      The worst year.Singapore’s largest dengue outbreak: 35,000+ cases. Releases cover about 8% of HDB blocks.Coverage: ~8% of HDB blocks covered. Mosquitoes: no published weekly total found. Sources: MSE, 2022; NEA via Malay Mail, 2022; NEA, 17 Jul 2020.
    6. 2021
      Fewer cases.Study sites in four towns: up to 98% fewer mosquitoes and up to 88% fewer dengue cases. Observational, not yet randomised.Coverage: 860 HDB blocks in Yishun and Tampines by June 2021. Mosquitoes: no published weekly total found. Source: NEA, 5 Jul 2021.
    7. 2022
      The trial.15 areas, about 724,000 residents. Eight are picked at random for releases. Seven get none.Coverage: About 300,000 households after the 2022 expansion. Mosquitoes: 2 million produced a week. Sources: NEJM, 11 Feb 2026; NEA via Malay Mail, 2022.
    8. 2023
      A million residents.Releases now reach more than 300,000 households and about 30% of HDB blocks.Coverage: 300,000+ households, about 30% of HDB blocks. Mosquitoes: 7 million a week: capacity. Sources: MSE, 8 May 2023; Debug, 2024.
    9. 2024
      96% say yes.In community surveys, 96% of residents accept releases in their neighbourhood. The trial ends in September.Coverage: 480,000 households from March 2024. Mosquitoes: 11 million a week: capacity. Sources: MSE, Feb 2024; MSE, 2024; Debug, 2024; NEJM, 11 Feb 2026.
    10. 2025
      Quietest since 2018.4,036 dengue cases nationwide. MSE credits no major outbreak, a global dip and mosquito control by everyone.Coverage: 580,000 households from April 2025. Mosquitoes: 11 million a week: capacity, latest published (2024). Source: MSE, 13 Jan 2026.
    11. 2026
      The verdict.71–72% lower dengue risk in release areas. 6% of tests positive, vs 21% in control areas.Coverage: 580,000 households (April 2025). 740,000 planned by March 2026.. Mosquitoes: 10 million+ Debug’s weekly releases (May 2026). Source: NEJM, 11 Feb 2026. 2,351 estimated dengue cases averted during the trial (95% CI 1,968–2,735). Same trial, second analysis. Source: eBioMedicine, 10 Sep 2026.
    DataDownloads, corrections, thanks and every source

    Data and corrections

    Every number in the film, with its source:

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    • v1.0, 2026-10-18. First published. Figures checked on 16 October 2026.

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    With thanks

    Sources

    1. NEA: Wolbachia-Aedes mosquito suppression strategy (programme page, updated 13 Aug 2026)
    2. NEA media release, 18 Oct 2016: small-scale field study begins at Braddell Heights
    3. NEA: Phase 1 small-scale field study, results and lessons
    4. NEA: Phase 2 field study, carried out in Tampines West and Nee Soon East
    5. NEA media release, 18 Sep 2018: Verily joins the ongoing Phase 2 field study, which started in April 2018
    6. MSE: Minister Grace Fu at the 5th Asia Dengue Summit, 15 Jun 2022 (2020 outbreak, Verily partnership, production of 2 million a week)
    7. NEA media release, 7 Oct 2019: more than 90% suppression in Phase 3
    8. Malay Mail, 15 Jun 2022, quoting NEA: 2020 study sites covered about 8% of HDB blocks; 2022 expansion to 31% of blocks or 300,000 homes
    9. NEA media release, 17 Jul 2020: 65–80% fewer dengue cases at Yishun and Tampines study sites in 2019 (preliminary); releases to cover both towns
    10. NEA media release, 5 Jul 2021: up to 98% suppression and 88% fewer dengue cases at study sites
    11. Lim JT et al. Dengue suppression by male Wolbachia-infected mosquitoes. N Engl J Med 2026;394:1175–83
    12. MSE written reply, 8 May 2023: more than 300,000 households, about 30% of HDB blocks, 1 million residents
    13. Debug blog, 15 Apr 2024: weekly capacity from 7 million (2023) to 11 million (2024)
    14. MSE written reply, 16 Feb 2024: 96% of residents accept releases
    15. MSE written reply, 2024: 480,000 households covered since March 2024
    16. MSE oral reply, 13 Jan 2026: 4,036 cases in 2025; 580,000, 740,000 and 800,000 households
    17. Impact of Wolbachia-mediated incompatible and sterile insect techniques on dengue incidence: a large-scale cluster randomised controlled trial. eBioMedicine, 10 Sep 2026
    18. Debug blog, May 2026: over 10 million released weekly from its Singapore facility
    19. Lim JT et al., Lancet Microbe 2024, and Bansal S et al., Lancet Planetary Health 2024: synthetic-control studies, as cited in the NEJM paper
    20. NEJM full text with acknowledgements, hosted by NEA
    21. NEA: automation and partnerships to scale capacity (Orinno, Verily)

    Independent tribute, not affiliated with or endorsed by NEA.