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Coronavirus pandemic: All stories
OpinionLetters

Letters | Hong Kong’s third wave: extend screening to sewage, try ‘pool testing’ for speed

  • Sewage testing, already adopted in Singapore and Australia, can detect community infections a week earlier than other tests while screening samples from pools of people rather than individually can also speed up the process

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Residents of Ping Shek Estate queue up to submit a saliva sample for testing on July 7 after an employee of a congee shop tested positive for Covid-19. Photo: Winson Wong
Letters
As Hong Kong has been hit by a third wave of Covid-19 infections, with double-digit cases recorded in the past few days, the government has suspended local schools and tightened social distancing rules.

To protect public health, the government must expand coronavirus testing through monitoring the virus in sewage water and implementing “pool testing”, while keeping the public fully informed about how it is handling the pandemic.

British researchers have recently advocated testing for the coronavirus in sewage as viral material is often found in human faeces. Through this, infected cases can be detected in specific communities a week earlier than by other existing tests, an approach that has been adopted in Singapore and Australia.

Since Hong Kong’s use of seawater to flush toilets may affect the method’s validity, a research team at the University of Hong Kong has been working to adapt the method. The Department of Health should work with local researchers and the Drainage Services Department to conduct sewage epidemiology for early detection of community outbreaks.

In Wuhan, the epicentre of the pandemic, the government managed to conduct coronavirus tests on 6.5 million residents in nine days to prevent a second wave of infections by adopting strategies such as pool testing.

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Hong Kong battles third wave of coronavirus infections

Hong Kong battles third wave of coronavirus infections

By combining samples from multiple individuals and testing them at one go (followed by individual tests only if the results are positive), the city significantly boosted its testing capacity to a level comparable to countries such as the United States.

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