Reporter: Li Chun

  In addition to nasopharyngeal swabs, oropharyngeal swabs, and serum tests, some centralized quarantine personnel in Beijing's Daxing District also recently conducted anal swab tests.

Cao Wei, deputy director of the Department of Infectious Medicine at Peking Union Medical College Hospital, said in an exclusive interview with a reporter from China News Agency that the addition of anal swab testing adds another barrier to epidemic prevention and control.

  According to the press conference on the prevention and control of the new crown pneumonia epidemic in Beijing on the 20th of this month, all students, faculty and staff of the school where the case was located in Daxing District have been tested for nasopharyngeal swabs, oropharyngeal swabs, anal swabs and serum .

The issue of anal swab detection has recently triggered a heated discussion on the Internet. "Why do you increase anal swab detection" is one of the main concerns of netizens.

  Photo by Wu Min issued by Xinshe in the data map

  Cao Wei introduced that whether it is from the follow-up data of people infected with the new coronavirus or the data during the "SARS" period in 2003, detoxification from the feces is a phenomenon that occurs in the process of coronavirus infection.

Generally speaking, the duration of a positive stool nucleic acid test will be longer than that of nasopharyngeal and oropharyngeal swabs.

  Returning to the prevention and control of the epidemic in Daxing District, Cao Wei pointed out that although the detection of viral nucleic acid in the stool does not necessarily mean that it is contagious, the increase in anal swab testing and the implementation of the "four-piece" test are undoubtedly in epidemiology. Another barrier has been added to the control, and the standards have become more stringent, helping to avoid the second spread of the virus.

  "People's understanding of the new coronavirus is still developing. Can you think that the virus infection takes a long time and the nucleic acid excreted is not infectious? In fact, more data support is needed." Cao Wei said.

  The two local confirmed cases reported by Beijing Daxing on the 17th of this month had virus samples highly homologous to the variants found in the UK.

Is the increase in anal swab testing to stop the spread of the mutant virus that may occur?

  Cao Wei said that anal swab detection has nothing to do with virus mutation.

Although there is a possibility that the detoxification pathway and duration of the virus may change after the virus mutates, from the perspective of screening, the increase in anal swab detection is not out of consideration for the mutant virus.

  Data map: Photographed by China News Agency reporter Zhang Chang

  Compared with the detection of oropharyngeal and nasopharyngeal swabs, the operation of anal swab detection is naturally more cumbersome, and may also cause psychological discomfort to the subject. Many netizens report that they are "embarrassed" and "too embarrassing."

  Cao Wei pointed out that anal swab testing requires more privacy in the operating place, and China has not previously used it for large-scale screening testing.

In areas where there are a large number of cases, such as epidemic areas and high-risk areas, anal swab testing will also impose higher requirements on the time and place where people need to be isolated, and it is "not likely to be extended to screening tests for all employees."

  Even so, under what circumstances might anal swab testing be extended to a wider range?

Cao Wei believes that due to the limited duration of nucleic acid-positive oropharyngeal and nasopharyngeal swabs, anal swab testing can play a part in supplementary screening when there are too many asymptomatic infections in the population.

  According to official reports, Beijing added two more local confirmed cases on the 25th, all living in Ronghui Community, Tiangongyuan Street, Daxing District.

Currently, the Ronghui community is still a high-risk area for the epidemic.

  Data map: On January 25, epidemic prevention staff carried out disinfection operations in Ronghui Community, Tiangongyuan Street, Daxing District, Beijing.

Xinhua News Agency reporter Sun Ruibo photo Source: Xinhuanet

  The special meeting of the Beijing New Crown Pneumonia Epidemic Prevention and Control Work Leading Group held on the afternoon of the 25th pointed out that the current epidemic prevention and control is still at a critical stage, and any hidden risks must not be let go. The string must be tightened at all times to fully implement the "quartet responsibility". , Strict social prevention and control, screening control and traceability of the circulation are both held tightly, and resolutely cut off the chain of virus transmission.

  Talking about why more rigorous "four-piece" testing methods should be adopted at the moment, Cao Wei pointed out that there have been many sporadic cases in Beijing recently, and the epidemic prevention and control situation is more severe.

According to observations in the past year, people have discovered that the new coronavirus has a certain ability to survive in natural environments such as physical surfaces and cold chains. The understanding of the importance of environmental management and monitoring also needs to be raised to a new level.

  On the other hand, there are also some exceptions, such as an extremely long incubation period, and the detection of nucleic acid positive or illness after the isolation period.

The previous dynamic analysis of the new coronavirus does not seem to be easy to explain this type of phenomenon.

"This situation also makes us pay more attention to environmental monitoring and potential detoxification methods."