Travelers to some Chinese cities were forced to undergo anal smear tests for COVID-19, a move that has sparked protests in other countries, according to press reports.
This week, Japanese officials complained that some Japanese citizens who arrived in China were subjected to tests, which “caused great psychological pain”. according to the BBC.
And in February, some U.S. diplomats said they were required to take the tests, which led to a complaint from the U.S. State Department, Vice reported.
“The State Department never agreed to this type of test and protested directly to the Ministry of Foreign Affairs when we learned that some officials were subject to it,” a State Department spokesman told Vice. (Chinese officials have denied that American diplomats have been asked to undergo anal tests, Vice said.)
It is unclear how many international travelers were required to take anal tests, but Beijing and Shanghai would have required testing for some arrivals, according to The New York Times.
Some Chinese doctors say the tests are carried out to detect silent carriers of the virus – those who may have no symptoms or develop mild symptoms, but recover quickly – because the new coronavirus can be detected in the stool longer than in the nose and throat.
“Some asymptomatic patients or those with minor symptoms recover quickly [from COVID-19], and throat tests may not be effective for these people, “Li Tongzeng, infectious disease doctor in China, told CNN.
“The researchers demonstrated that, for some infected people, the duration of the positive nucleic results lasted longer in their excrement and anal smear test. [samples] than those in the upper respiratory tract. Therefore, adding anal swab tests can improve the rate of positive detection of those infected, ”he said, referring to the so-called PCR diagnostic tests for the virus.
Some Chinese citizens were also required to take anal tests COIVD-19. In January, more than 1,000 students and teachers in a school district in Beijing received anal smear tests, as well as nasal smear tests, for COVID-19 after a 9-year-old student in the district tested positive, according to the vice. Other people staying in quarantined hotels were asked to take the tests. One person told Vice that he was asked to have an anal test in September 2020, while in a quarantine hotel after returning from Australia. He said the test was administered by nurses and that “it looked like he was having diarrhea,” reported Vice.
The tests have sparked controversy among experts, even in China. Yang Zhanqiu, deputy director of the pathogen biology department at Wuhan University, told the state-controlled Chinese newspaper that Global Times in January, nasal and throat tests were still more effective than anal tests, because the virus is known to spread through respiratory droplets rather than through feces. If the purpose of the tests is to prevent an infected person from spreading the virus, the argument goes, then nasal / throat tests would work better.
“There have been cases related to a positive coronavirus test in a patient’s droppings, but no evidence suggests that it was transmitted through the digestive system,” said Yang.
Experts outside China also question the practice, since those who tested positive for COVID-19 on an anal test but not on a nasal or throat test would probably not be very contagious, according to The New York Times.
“The value of detecting people with the virus is to stop transmission,” Benjamin Cowling, a professor of public health at the University of Hong Kong, told the Times. “If someone caught an infection, but it is not contagious to anyone, we don’t need to detect that person.”
Originally published on Live Science.