China has started using anal swabs to test for coronavirus because they are “more effective” than the nose and mouth.
Some cities, including the capital Beijing, are using samples from the anus to detect infection, while the country is stepping up screening before the New Year holidays.
For anal swabs, a cotton swab 3 to 5 centimeters long must be inserted into the anus and carefully rotated.
People in areas with confirmed cases as well as in designated quarantine facilities have been anally wiped, reports the state television broadcaster CCTV.
It comes after multiple outbreaks in the north of the country, with Chinese officials running test campaigns to avoid regional contamination.
Several cities have also been cordoned off.
Infectious disease doctor Li Tongzeng said traces of the virus in anal swabs and stool samples could remain detectable longer than upper respiratory samples.
Such wiping “can increase the detection rate of infected people,” the chief doctor of Beijing Youan Hospital told CCTV.
Last week, over 1,000 teachers, staff and students at a Beijing elementary school had anal swabs taken after an infection was found, a city official said.
Her nose and throat swabs and serum samples were also
collected for testing.
Researchers from the Chinese University of Hong Kong (CUHK) said stool tests might be most effective at identifying Covid-19 in children.
In an article published in 2020, CHUK experts said children and infants have higher viral loads in their feces than adults.
A throat swab on a 52-year-old man in Weinan, a city in northern Shaanxi Province, reportedly showed a negative result, despite exhibiting several tell-tale symptoms of Covid.
The patient, who developed a cough and had loss of appetite, retested with anal and nasal swabs, which came back positive.
Dr. Li added that anal samples are only required for key groups like those under quarantine.
As CCTV said, officials are unlikely to condone the use of anus tests on the same scale as other methods because it is “not convenient”.
As cases increase, China has tightened internal restrictions, and people from medium and high risk areas have been banned from the capital since last week.
And arrivals in the country must provide multiple negative test results and be quarantined in a specific hotel for at least 14 days.
Many cities and regions have additional requirements for house observation.