Authorities in Beijing are ordering anal swabs for some people who may have contacted COVID-19 patients, in its latest effort to contain local outbreaks.
Officials said last Wednesday that anal swabs had been administered for more than 1,000 students and teachers at a school in Daxing district in the Chinese capital, after a nine-year-old boy tested positive for the coronavirus.
Although China successfully contained the epidemic in the second half of 2020, the country is now facing new clusters linked to virus variants from overseas, which put renewed pressure on the government.
Anal swabs for coronavirus testing are not new in China. Some hospitals have been testing the rectal samples or feces of confirmed patients, after studies found that the coronavirus could be detected in people’s digestive system for longer than in their respiratory tract.
According to guidelines published by the National Health Commission, cotton swabs should be put 3 to 5 centimeters (about 1 to 2 inches) inside the rectum during an anal swab.
Alex Wang, 21, told VICE World News that he had two anal swabs at a quarantine hotel in September, after he returned from Australia to his hometown Weihai, in the eastern province of Shandong.
Wang said two nurses told him to hold onto a chair and use one hand to pull his buttocks apart. The swab lasted a few seconds. Wang said it felt like he was having diarrhea.
“At first I was shy,” Wang said. “But I understood the country was under pressure to prevent outbreaks.”
But the report about large-scale anal swabs in Beijing has prompted a wave of panic online, as people worry the unpleasant test will be rolled out to the general public.
“The nasal one was uncomfortable enough, I can’t imagine this one,” a Weibo user commented.
“I’m worried I will fart while being swabbed,” another person said.
Li Tongzeng, a doctor at the Beijing You’an Hospital, told state broadcaster CCTV that in some mild and asymptomatic cases, the virus could only be detected in anal samples but not in the respiratory swabs.
Li said conducting both anal and throat swabs would reduce the chances of missed infections. But since it’s not convenient to do anal swabs for large numbers of people, the test is now only required for the “key population,” such as those under quarantine, he said.
Researchers have been studying if anal swabs could help doctors screen potential infections or identify severe cases at an early stage.
A study in Weihai found the coronavirus was positive in anal swabs but negative in other sample types of several cured patients. Another study in the southern city of Guangzhou showed the detection of the virus in anal swabs was a potential warning indicator of severe disease.
Researchers are still trying to confirm whether the coronavirus can transmit through feces or urine. One study about an outbreak at an apartment building in Guangzhou suggested the virus might have spread through the wastewater system.
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