https://www.globaltimes.cn/page/202101/1213668.shtml
Beijing tests for COVID-19 using anal swabs, where virus may survive longer
Beijing reported a 9-year-old boy tested positive for COVID-19 last week, and his school conducted a variety of tests including serum antibody tests, nasal, throat, and even anal swabs for all its staff and students, prompting many to wonder if anal swabs could be more accurate in detecting the virus than other measures.
Li Tongzeng, a deputy director in charge of infectious disease at Beijing You'an Hospital, said that studies have shown that the coronavirus survives longer in the anus or excrement than those taken from upper body tracts, and for some silent carriers the virus may be present in their throats for 3 to 5 days, allowing some tests to provide false negative results.
Taking an anal swab could increase accuracy in key groups, Li noted during an interview with the China Central Television. However, given that the method is not as convenient as throat swabs, it will only be applied to key groups at quarantine centers.