
LettersHong 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
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.
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.

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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.
Simon Wang, Kowloon Tong
Allow alternatives for those who can’t use masks
I have a medical certificate that states I cannot wear a mask “due to the mask provoking a severe asthma attack”. Among the instructions that came with a government-issued CuMask+ is the statement: “Stop wearing the mask if it hinders breathing”.
Why has wearing a face shield not been made an alternative to a face mask? I cannot move around Hong Kong without using public transport. What does Chief Executive Carrie Lam Cheng Yuet-ngor or Health Secretary Sophia Chan Siu-chee suggest I do?
Julie Moffat, Ma On Shan
Why are South Asian countries on high-risk list but not US?
Why is the country that ranks the highest in the world in cases and deaths not on the list, while thousands of Hong Kong permanent residents, including those like me with Chinese nationality, are effectively barred from the city and country they call home?
The British government chartered dozens of flights out of India and Pakistan. I still do not understand why our Immigration Department is unable to do so, especially when the entire apron of Hong Kong airport is filled to the brim with parked planes. A cynical thought suggests racism.
Deepen Nebhwani, Yuen Long
