SHANGHAI/Wuhan, the epicentre of the coronavirus outbreak in China, has tested over three million residents since April, and will now focus its testing efforts on the rest of its 11 million population, according to state media.
Once testing of everyone in the city is completed, the authorities should have a clear indication of the number of asymptomatic cases as businesses and schools reopen, the official Xinhua news agency reported late on Thursday.
Priority will be given to residents who have not been tested before, people living in residential compounds that had previous cases of infection, as well as old or densely populated estates, Xinhua said, citing a Wuhan government meeting.
Fears of another wave of infections flared over the weekend, after Wuhan reported a cluster of cases, the first since a virtual lockdown on the city was lifted on April 8. The latest infections were previously asymptomatic cases, people who had the virus however, showed no symptoms such as fever.
Reuters, citing an internal document for district officials, reported on Monday that the city planned to conduct the testing campaign over 10 days.
Some experts say the mass testing is unprecedented in scale and shows the level of concern. Others warn of potential testing errors due to the sheer size of the sampling.
Some countries, like South Korea and Germany, have aggressively tested and traced infections, albeit at much lower levels than Wuhan is attempting.
In the United States, the rate of testing is still far short of the three million to five million tests per week that experts say will be necessary to safely reopen the country.
It is not clear how Wuhan will procure enough testing kits and process all the samples, and whether such a broad, systematic approach is the best use of resources when the city's infections are low.
Even state media reports have acknowledged the difficulty of the task. The official Health Daily newspaper reported on Thursday that the authorities would have to conduct at least 730,000 tests a day to finish within 10 days, even after excluding people who had been recently tested.
That is several times the current testing capacity in Wuhan, which the paper said could conduct 100,000 tests a day under extreme circumstances.
The Health Daily said the testing in Wuhan is free and the cost of the campaignwhich it estimated would exceed US$140 million (S$199 million)would likely be borne by the city.
Wuhan, by far the hardest-hit Chinese city, has reported more than 50,000 infections and 3,800 deaths since the outbreak started.
Recently, the city has detected up to more than a dozen asymptomatic infections every day.
One senior Chinese expert said it was unnecessary to test every resident in Wuhan, given the low number of cases in the city.
Dr Wu Zunyou, chief epidemiologist of the Centre for Disease Control and Prevention, told state television on Tuesday that large-scale testing should focus on "key areas and key groups".
"In communities without infections, there is no need to screen everyone," Dr Wu said.
REUTERS, NYTIMES