2 weeks out from the Olympics, China is back to using anal COVID-19 swab tests on some Beijing residents to try to detect Omicron cases

• Beijing is doing anal swabs on a small segment of its population to detect Omicron cases.
• 27 people were swabbed this week in the procedure, which involves a cotton bud being inserted close to two inches into the rectum.

In a bid to ring-fence COVID-19 cases and stop the spread of the Omicron variant in the run-up to the Beijing Winter Olympics, China is resorting to anally swabbing a small segment of its population.

According to Chinese news outlet The Beijing News, at least 27 people at an apartment building in Beijing's Haidian district were given anal swabs this week. Haidian district is where an infected woman — Beijing's first reported Omicron case — lives.

These anal swabs involve inserting a cotton swab around one to two inches into the rectum. The swab is then tested at a lab and analyzed the same way as Polymerase Chain Reaction (PCR) coronavirus tests performed on nose or throat samples.

Chinese state-linked media outlet Global Times reported in January 2021 that while most people were swabbed via nose or throat swabs, authorities used anal swabs for "key groups" of people sent to quarantine centers to increase the accuracy of the test.

Insider's Catherine Schuster-Bruce spoke to Joanne Santini, professor of microbiology at University College London, about the anal swabs. Santini told Insider that while anal swabs are not pleasant ways to test for COVID-19, it makes sense and is "the obvious thing to do" to detect an existing viral load that nose or throat swabs might not pick up.

While the test may be scientifically sound, it did cause some controversy in February 2021, when the US accused China of forcing American diplomats to take anal swab tests — which China denied. The Japanese government also registered a similar complaint with China, telling Beijing to stop requiring anal swab tests for its citizens, citing "psychological pain" and distress.

While the Chinese capital has not gone into complete lockdown, all inbound travelers are now required to get an additional COVID-19 test within 72 hours of arriving in the city, per a report from Beijing Daily.

Beijing detected its first Omicron infection around a week after Tianjin, a neighboring northern city, reported 97 COVID-19 cases. Officials there subjected the entire population of 14 million people to compulsory COVID-19 testing.

It's commonplace for Chinese cities to issue swift lockdowns if small clusters of COVID cases are discovered, per China's COVID-zero policy. Authorities locked down Xi'an, a city of 13 million people, after recording about 1,000 COVID-19 cases between December 9 and December 23. Similar lockdowns also happened in Yuzhou, a central Chinese city home to 1.2 million people, and Anyang, a city of 5.5 million residents.

The lockdowns come amid preparations for the Beijing Winter Olympics, which are set to kick off on February 4. The country plans to implement a "closed-loop" bubble, in which athletes, officials, broadcasters, and journalists may move only within designated locales.

Despite the recent upswing in infections, China has managed to keep its case numbers relatively low. According to the country's National Health Commission, 66 cases were detected across 31 provinces on January 20, bringing the number of active cases to 3,297. Of these, Beijing reported three instances of local COVID-19 transmission.