China has begun using anal swabs to test those it considers at high risk of contracting COVID-19, state TV reported, with social media users and travellers squirming over the invasive procedure which doctors say can be more effective in detecting the virus. Officials took anal swabs from residents in Beijing last week, broadcaster CCTV said, while those in designated quarantine facilities have also undergone the test.

Small, localised outbreaks in recent weeks have seen multiple cities in northern China sealed off from the rest of the country and prompted mass testing — which up until now have mostly been conducted using throat and nose swabs. But the anal swabs method “can increase the detection rate of infected people” as traces of the virus linger longer in the anus than in the respiratory tract, Li Tongzeng, a senior doctor from Beijing’s You’an Hospital, said.