"To my knowledge, China has never required U.S. diplomatic staff stationed in China to conduct anal swab tests," he said.
Last week, the Washington Post reported that some workers told the Department of State that they had been subjected to the tests.
"The state department never agreed to this kind of testing and protested directly to the Ministry of Foreign Affairs when we learned that some staff were subject to it," a state department spokesperson said.
It is not known how many U.S. diplomats have taken the test.
The state department claimed that it was told by Beijing that the test was given "in error" as diplomatic personnel were exempt from it. A representative of the department reiterated its commitment "to guaranteeing the safety and security of American diplomats and their families, while preserving their dignity." The supposed anal swabbing of U.S. diplomats sparked a significant chatter on Chinese social media platform Sina Weibo.
Many users joked about how Americans are so potty-mouthed when it comes to China that it would be expected they would mistake an oral swab for an anal one. Some questioned the authenticity of the U.S. diplomats' claims and perceived that this was just another "rumor" to "discredit" China over its handling of coronavirus.
There had been a lot of bad sentiment between the U.S. and China, particularly during the Trump administration. China criticized the U.S. government for exacerbating anti-Chinese sentiment by repeatedly calling coronavirus the "China virus" and "Kung flu."
China introduced anal swabs in January as experts claimed they could "increase the detection rate of infected people." Some Chinese cities used samples taken from the anus to detect potential infections amid intensified screening during a spate of regional outbreaks ahead of the Lunar New Year holidays. (Related: China now using anal swabs to detect coronavirus.)
Reports said the test is mandatory for incoming travelers in some parts of China.
To collect test samples, a cotton swab should be inserted about three to five centimeters into the rectum and rotated gently. After completing the motion twice, the swab would be removed before being securely placed inside a sample container. The whole procedure would only take a few seconds.
Li Tongzeng, a respiratory and infectious disease doctor in Beijing, told state media that anal tests could avoid missing infections as virus traces in fecal samples are detectable for a longer time than the more common coronavirus tests used in the mouth and nose. But he noted that anal swabs are only needed for certain people such as those under quarantine.
Researchers at the Chinese University of Hong Kong said in a paper published last year that stool tests could be more effective in finding infections in children and infants as their waste carries a higher viral load than adults.
But some experts were not convinced.
Yang Zhanqiu, a deputy director of the pathogen biology department at Wuhan University, told state media Global Times that the nasal and throat swabs remain the most efficient test as the virus is proven to be contracted via one's 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," Yang said.
Beijing began using anal swabs more frequently after a nine-year-old boy tested positive for the virus last month. Authorities said, more than three million residents in three Beijing districts had been tested for coronavirus last month in a bid to stem the infection.
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