[Global Times-Global Times Reporter Fan Lingzhi, Bai Yunyi, Liu Caiyu, and Zhao Juehui] According to the press conference on Kashgar epidemic prevention and control held by the Press Office of the People’s Government of Xinjiang Uygur Autonomous Region on the 31st, from 24:00 on October 30 to 18:00 on October 31 , Xinjiang has newly reported 61 cases of asymptomatic infections, including 46 cases in Shufu County, and 15 cases in Akto County, Kizilsu Kirgiz Autonomous Prefecture (Kezhou), which is adjacent to Shufu County.
Chinese epidemiologists told the Global Times reporter on the evening of the 31st that the 61 newly-infected patients may not be detected because they were in the early stage of the first round of nucleic acid testing. This detection may be "eliminating dead ends." "The necessary steps.
However, experts remind the local area to be highly vigilant, and the related prevention and control dead ends and the source of the virus need to be found through detailed epidemiological investigations.
Why are there 61 new cases? Expert: It is necessary to fail to detect repeated tests in the early stages of infection
According to the official report, due to the junction of Akto County, Atushi City, and Wuqia County in Kezhou with Shufu County in Kashgar Prefecture, after the outbreak in Shufu County, Kezhou completed the nucleic acid test for all employees on the 27th, and the results were all Negative.
On the 30th, Kezhou carried out the second round of free nucleic acid testing for key populations in key areas. From 24:00 on the 30th to 18:00 on the 31st, 15 cases of asymptomatic infections were newly reported in the neighboring towns of Akto County and Shufu County. All personnel under medical observation.
The two rounds of free nucleic acid tests for all employees in Kashgar were completed on the 27th and 31st, respectively. Except for the confirmed cases and asymptomatic infections that have been announced, the test results of the rest were negative.
That is to say, including the newly notified 61 cases of asymptomatic infections, all new asymptomatic infections are from Zhanmin Township and surrounding townships in Shufu County, and all are personnel under quarantine medical observation.
A medical expert from Xinjiang told the Global Times on the 31st that these 61 asymptomatic patients were negative in the first round of nucleic acid tests, and then the second round of nucleic acid tests were positive. There may be two situations: one is They may be in the early stages of the disease, and the nucleic acid test could not be detected. The expert’s judgment is also consistent with the situation reported at the press conference of the autonomous region. Gu Yingsu, deputy director of the Xinjiang Health Commission, said that the new coronavirus has gone from infection to detection. There is a certain time interval for the detection. If the first nucleic acid sampling happens to fall within this time interval, it may not be detected.
According to the incubation period of the new coronavirus, the incubation period of new coronary pneumonia is 1 to 14 days, and the common incubation period is 3 to 7 days. This means that about 90% of people will have a positive nucleic acid test within 3 to 7 days after being infected with the virus, and some People are less than 3 days, and some people are more than 7 days.
The above-mentioned experts believe that another possibility is the existence of "false negatives".
This is why Kashgar and surrounding areas have launched the second round of nucleic acid testing.
Chen Xi, associate professor of the School of Public Health at Yale University, said in an interview with the Global Times on the 31st that the repeated nucleic acid testing being implemented in Xinjiang is necessary. If the scope of infection is not large, repeated testing can avoid statistical errors due to "false negatives". "After all, throat swabs are sampled in the upper respiratory tract, and the virus content is often low in the early stages of infection." According to Gu Yingsu's introduction at the press conference, the second round of nucleic acid testing is to accurately identify and screen in the shortest time. Those who are still in the incubation period.
This is not only conducive to the implementation of the "four mornings" requirements, to buy time for early treatment and early recovery, but also to prevent the spread of the epidemic, and make every effort to protect the lives and health of people of all ethnic groups.
Chen Xi also mentioned that there may be a gap between the medical transportation conditions in Xinjiang and the mainland. If the samples are collected too early or too late, or the samples are not properly stored, transported, and processed, they may face challenges.
New infections or "removal of dead spots" are necessary steps but still need to be highly vigilant
Since the 15 new cases in Kare Kaiqike Township and Pilal Township of Aktao County are adjacent to Shufu County, the above-mentioned Xinjiang experts believe that it is not ruled out that the epidemic has spread in these places at the beginning. Close contacts or close contacts of close contacts, but the specific transmission trajectory is unclear.
However, the expert said that Kezhou, like Shufu County, adopted home quarantine measures in the early stages of the epidemic. Although there are signs of early spread of the epidemic in the community, these potential cases have now been detected, "as long as they are detected. The epidemic can be controlled".
"The newly discovered infection may be a necessary step to'remove dead spots'. Only through this step can we grasp the population's infection situation as much as possible." Chen Xi said.
Wang Guangfa, director of the Department of Respiratory and Critical Care Medicine at Peking University First Hospital, told the Global Times on the 31st that if measures are taken properly and there are no obvious loopholes in prevention and control, the number of new cases will drop in about 7 days, and the number of new cases will fall in about 14 days. There is a significant decline.
Therefore, he believes that whether the epidemic situation in Xinjiang is completely controlled requires a few more days of observation, and now we should maintain a high degree of vigilance.
Expert: The prevention and control of dead ends and the determination of the source of the virus need to be found by epidemiological investigation
Wang Guangfa believes that from the public information, the new cases are still asymptomatic infections. This shows that the local screening is very timely, but on the other hand, it may also indicate that the situation is not too optimistic. The symptoms are mild, but they are still contagious." If the asymptomatic infections continue to appear, it means that there may be some dead ends in prevention and control.
"These blind spots require detailed epidemiological investigations to find out. Because of language and other factors, it may be difficult to conduct circulation in ethnic areas, but this is a work that must be strengthened."
"The prevention and control of infectious diseases mainly consists of three items: controlling the source of infection, cutting off the route of transmission, and protecting susceptible persons. The most important of these is to control the source of infection. If the source of infection is not known, prevention and control will be very difficult." Wang Guangfa said that if the source cannot be found, it will be difficult to “block” the virus in the first place. The virus may continue to emerge from this channel, and it will be difficult for people who were in contact with this source to be discovered in time, which may change. Into a new source of infection.
For example, the source of the epidemic situation in Shufu County has not yet been clarified, so was the epidemic situation in Aktao County, which was nearby, passed from Shufu County?
Or is it the source of Shufu County?
It is still impossible to tell, "The place where the epidemic occurred afterward may not necessarily be the'downline' that was passed on. It may also be the source, or it may be two branches that spread from the same source."
Chen Xi also expressed the same view. He believes that in addition to testing, the work of tracking close contacts is very important at this moment, because this can stifle community transmission in the bud, so as not to have to carry out a wider range of closure in the future.
Wang Guangfa finally suggested that Xinjiang should quickly screen and track the flow of cold chain food and key personnel associated with the concentrated outbreak in Shufu County. "This may be more efficient than undifferentiated large-scale whole-employee testing, because The most important thing now is to be fast."