China rolls out anal swab tests to detect high-risk COVID-19 cases, says its more effective

As Chinese authorities rush to contain rising Covid-19 infections ahead of the Lunar New Year holidays next month, some cities in the country have introduced a new type of Coronavirus test. According to The Guardian, Beijing began using anal swabs last week, as a supposedly much more effective method to detect potential COVID-19 infections. Officials reportedly took anal swabs from residents of neighbourhoods with confirmed Covid-19 cases in the city and from those in designated quarantine facilities. China has been battling new pockets of outbreaks in the north and northeast in recent weeks, resulting in strict lockdowns and mass testing campaigns in a bid to stamp out the outbreaks.

According to Forbes, state-run channel CCTV reported that the anal swab tests are reserved for high-risk cases. However, there does not appear to be a coordinated policy for them as there have been reports of surprise tests for some individuals. Li Tongzeng, deputy director of the respiratory and infectious diseases department at Beijing Youan Hospital, said in an interview with state media that the anal swabs method — which involves inserting a cotton-tipped swab three to five centimeters (1.2 to two inches) into the rectum and gently rotating it — "can increase the detection rate of infected people."

Li added that studies indicate that the novel Coronavirus lasts longer in the anus or excrement than in the respiratory tract and that an anal test, therefore, could be better at detecting the virus in mild or asymptomatic cases. Further justifying the decision to take anal swabs — which would reportedly not be used as widely as other methods since the technique is "not convenient" — a city official in Weinan in northern Shaanxi province cited the case of a 52-year-old man with symptoms including coughing who initially tested negative for COVID-19.

According to Al Jazeera, the official said that the man was later confirmed to have the virus when tested via an anal swab. The man had been confined to a centralised facility for medical observation after he came in close contact with another COVID-19 patient earlier this month. In a video posted online by the state-backed newspaper Global Times, Zhang Wenhong of Huashan Hospital in Shanghai reportedly said that anal swabs could also be useful in helping minimize the risk of relapse after recovery. "There may be traces of the coronavirus detected in the abdominal cavity faeces and intestine," Zhang was quoted as saying.

A Beijing city official said last week that anal swabs were taken from over 1000 teachers, staffers, and students at a primary school in the city after an infection was detected there. Nose and throat swabs and serum samples were also collected for testing. Meanwhile, the use of anal swabs to test for a respiratory illness has been controversial among certain experts. Yang Zhanqiu, a deputy director of the pathogen biology department at Wuhan University, told reporters that nasal and throat swabs are still the most effective means to detect the virus since the novel Coronavirus has proven to be contracted via the upper respiratory tract rather than the digestive system.

"There have been cases concerning the coronavirus testing positive in a patient's excrement, but no evidence has suggested it had been transmitted through one's digestive system," said Yang. Users of Weibo — China's Twitter-like social media platform — reacted to news of the anal swab method with a mix of mirth and horror. "Low harm, but extreme humiliation," one user is said to have commented while another joked: "I've done two anal swabs, every time I did one I had to do a throat swab afterward – I was so scared the nurse would forget to use a new swab."