China has approved seven more rapid antigen test (RAT) kits for Covid-19, bringing the total to 12 as the country races to stop the spread of the Omicron variant severely challenging its zero-Covid defences in place since 2020. In a break with past policy of only carrying out nucleic acid tests to confirm infections, the National Health Commission on Friday authorised the use of RATs by the public “to optimise detection of Sars-CoV-2” , the coronavirus that causes Covid-19. Test kits from five companies were approved the same day. By Wednesday, seven new products had been added to the list. This comes as China grapples with a growing number of Omicron infections, with outbreaks in at least 16 provinces and more than 18,000 positive cases logged since the beginning of March. Li Jinming, deputy director of the NHC’s Clinical Testing Centre, said nucleic acid tests remained the main means of identifying Covid-19 infections, but RATs should play a complementary role. Li said such tests were mostly for three types of people: those who still had symptoms five days after onset but tested negative on nucleic acid tests; travellers or close contacts in quarantine; as well as those who tested negative on nucleic acid tests but found it “necessary” to test again. Antigen tests may produce false positive results, he cautioned, saying they could not be used as definitive diagnosis. RATs pick up the protein of the virus without amplification and are therefore believed to be less accurate than nucleic acid tests. China had shunned the tests in the two years since the pandemic first broke out, although they were widely deployed in the West. This is the first time RATs have been made commercially available in China. The worst-hit northeastern province of Jilin, which accounted for 60 per cent of local symptomatic cases on Tuesday, aims to buy 12 million of the rapid test kits. The spike in cases was being caused by the BA2 sub-variant of Omicron, which is even more infectious, according to Lei Zhenglong, deputy head of the NHC’s Bureau of Disease Prevention and Control. Identifying cases was difficult because most patients showed little or even no symptoms, Lei said. On the drugs front, Chinese regulators gave conditional approval to Pfizer’s Covid-19 pill Paxlovid last month and it has been added to the latest NHC guidelines for clinical use. Paxlovid is the first foreign Covid-19 treatment to be approved by mainland authorities. Jin Dong-Yan, a molecular virologist with the University of Hong Kong, said antigen tests should be widely used in the mainland, as these could pick up patients with high viral loads and reduce transmission risks from long queues for nucleic acid tests. He said RATs, although less sensitive than nucleic acid tests, were able to pick up people who are contagious. “That [finding those who are contagious] is what really matters in public health.” Given the size of the country and weak health care infrastructure in rural areas, “it would not be realistic if they only rely on the nucleic acid tests”, Jin added. China’s zero-Covid policy to stay but may be fine-tuned, premier says Nicholas Thomas, an associate professor at City University of Hong Kong’s Asian and international studies department, said it was becoming increasingly difficult for mainland China to keep up its zero-tolerance approach, and called for preparations to tackle uncontrolled outbreaks. “If the Omicron wave pattern mimics what we have seen overseas, then we should expect cases to continue to rise for the next three to five weeks,” he said. “However, the asymptomatic nature of the variant coupled with the wide geographical dispersal of the outbreaks may challenge Chinese authorities’ abilities to track and test to the same level as they have done in the past,” Thomas said. “At the same time, there are reports showing that pandemic fatigue is now more present in China than before, which might limit the numbers of people who are willing to come forward if they have slight symptoms.”