In Wuhan, swab samples are being mixed to carry out quick group tests

The mass testing is part of China’s efforts to fortify against a potential “second wave” after a cluster of cases emerged in a residential community earlier this month.

Chinese health authorities in Wuhan carried out mixed testing of nose or throat swabs of residents to check for Covid-19 so that millions of samples could be tested in quick time, local media reports said.

Between May 15 and 25, Wuhan medics tested more than 6.5 million residents, a state media report said, adding at least 218 among them were found to be asymptomatic.

The current nucleic acid tests are being carried out after Wuhan where the coronavirus emerged late last year opened up on April 8 after a 76-day lockdown.

Wuhan, a city of 11 million people, was badly affected by the outbreak, accounting for over 50,000 infections and around 3,800 deaths.

The mass testing is part of China’s efforts to fortify against a potential “second wave” after a cluster of cases emerged in a residential community earlier this month.

To carry out the tests in time, health workers collected and mixed 10 to 20 samples and carried out a single test on them; If the collected sample was positive, each individual was tested again to identify which person was positive.

An unnamed medic told the Caixin news website that the authorities believed that the approach works well as long as the testing follows procedure.

“Disease control agencies have used this approach before and trial testing is usually conducted in advance to set a minimum concentration level for testing,” the staff member told Caixin.

“This is the only way to speed up the process, otherwise Wuhan cannot test as many samples within such a short time,” Peng Zhiyong, director of the intensive care unit of the Zhongnan Hospital of Wuhan University, told state media.

The largest single-day number tested was on May 22 when 1,470,950 nucleic acid tests were performed.

The local health commission said the tests are being carried out free of charge. Priority was given to residential compounds that had previously reported infections, as well as old and densely populated compounds.