Project Wolbachia prevents dengue in Singapore

30/03/2026 3 Views

SINGAPORE – The expansion of Project Wolbachia in 2022 helped avert 3,798 cases of dengue – or about 28 per cent of expected cases – in 2023, according to a predictive model developed by international researchers and the National Environment Agency (NEA).

Using climate data and data on the four dengue serotypes, or strains, researchers estimated that 13,748 cases would have occurred in 2023 had the initiative not been expanded in the previous year.

Singapore reported 9,950 cases of dengue in 2023, with six deaths from the disease.

First launched in 2016, Project Wolbachia is an initiative to control the Aedes mosquito population here through the release of lab-grown male mosquitoes infected with the Wolbachia bacteria.

In 2022, NEA expanded Project Wolbachia from an initial five locations to an additional eight sites – including Hougang, Choa Chu Kang and Woodlands – covering more than 300,000 homes here.

By October 2026, more than 800,000 households here, or half of all households in Singapore, will be covered by Project Wolbachia as part of efforts to prevent the spread of dengue.

Research published in the New England Journal of Medicine in February found that the Aedes aegypti mosquito populations were reduced by 80 per cent to 90 per cent in areas covered by Project Wolbachia, with the dengue risk for residents in these areas falling by more than 70 per cent.

The new predictive model incorporates elements such as the monthly case percentages of the different dengue virus serotypes, data on the El Nino and La Nina phenomena, as well as the average monthly maximum temperature and total monthly rainfall.

Including data on the different dengue serotypes enhanced the predictive ability of the model beyond that of climate data alone, the researchers said. They found that incorporating climate information made the model 54 per cent more accurate than relying solely on seasonal case data, while incorporating information on the dominant dengue serotype improved its accuracy to 60 per cent.

Basing their study on over 20 years of data, the research team found that the risk of a dengue outbreak was highest during El Nino conditions and in the first few years following a change in the dominant dengue serotype.

The model is able to identify periods with higher dengue risk up to eight weeks in advance

The study was led by Dr Emilie Finch, a PhD student at the London School of Hygiene and Tropical Medicine at the time of the research, and Professor Rachel Lowe, a visiting professor at the NUS Saw Swee Hock School of Public Health.

The findings were published in the scientific journal Nature Communications in November 2025.

Associate Professor Ng Lee Ching, group director at NEA’s Environmental Health Institute, described the predictive model as a “valuable addition” to the agency’s range of tools for risk assessment.

Both the impact of climate and changes in circulating dengue serotypes were used as a proxy for changes in population immunity, said Dr Finch, now a postdoctoral researcher at the University of Cambridge’s pathogen dynamics unit.

“This allowed us to disentangle the effects of climate and serotype changes on dengue transmission in Singapore and improved our ability to predict dengue surges,” said the visiting researcher at the Barcelona Supercomputing Center’s (BSC) Global Health Resilience group.

“By combining climate information with disease surveillance, advanced modelling and high-performance computing, we can better understand how climate variability influences dengue dynamics,” said Prof Lowe, who also leads the Global Health Resilience group at BSC.

In 2025, there were 4,036 dengue cases here – a 70 per cent drop from the 13,651 recorded in 2024. According to NEA, 375 dengue cases were reported here in 2026 as at March 21, down 63 per cent from the 1,021 cases over the same period in 2025.

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