HKUMed MFN v26i1

Professor Zhang Tong, Department of Civil Engineering 㕼加䊨玑禺䓹䕒來䱇 Professor Zhang tracked the progress with the happy enthusiasm of his cartoon namesake, checking his phone repeatedly for updates. ‘I remember one night I showed my wife our table of hotspots – it had so many red spots where the virus was found in sewage. Soon after that there were many cases reported in the community. That was the beginning of Hong Kong’s fourth wave.’ In late December, following three consecutive days of positive signals from sewage samples in Fung Chak House, the government decided to issue its first compulsory testing notice. The research had thus provided evidence that became the basis for government policy. The team subsequently developed methods to identify COVID-19 variants in sewage. The new testing method was applied in early June to test a sewage sample collected on May 2, 2021 from Hing Wah (II) Estate (Chai Wan), and successfully identified positive signals of N501Y and other mutations of the Beta variant (known as B.1.351, first identified in South Africa). A positive case involving the COVID-19 Beta variant in that area had been confirmed on May 7, 2021. Recently, they also detected the Delta variant in a sewage collected from Tai Po on June 21, providing early warning signal for the community before the first clinical Delta variant case was found on June 23, 2021. These successes are a welcome reward for the researchers, who initially spent months until late in the evening, sometimes midnight, processing samples so the results could be reported to the government by the next morning. ‘This is a good story about collaborations among different faculties and between the University and the government,’ said Professor Zhang, who is keen to share the credit and maintains a childlike wonder at the possibilities of science. ‘Our role in sewage surveillance can help not just with COVID-19, but other human pathogens, too. Sewage may tell the health of a city, and we are learning how to listen to it.’ ‘Sewage may tell the health of a city, and we are learning how to listen to it.’ չ寓宐〳⟃デ鏰䧮⦛♧⦐㙹䋑涸⨴䐁朜屣 䧮⦛姻㖈㷸绢㥶⡦⫙聃պ – Professor Zhang Tong 䓹䕒來䱇 19