The number of new local infections has exceeded 20,000 for seven consecutive days. What are the difficulties in precise prevention and control?

Ten days after the twenty optimization measures were released, on the afternoon of November 21, the State Council’s Joint Epidemic Prevention and Control Mechanism Comprehensive Team issued four documents, respectively focusing on how to implement nucleic acid testing and the delineation of risk areas after policy adjustments. Detailed guidelines have been formulated in four aspects: management and control, home isolation and home health monitoring.

These guidelines basically integrate and summarize the contents of the ninth edition of the prevention and control plan and the "Twenty Points", and further elaborate on key issues such as how to carry out normalized nucleic acid testing, de-escalation of high-risk areas, and home isolation objects. It is clear and provides policy basis for local governments to achieve precise prevention and control.

At the press conference of the Joint Prevention and Control Mechanism of the State Council held on November 17, Shen Hongbing, deputy director of the National Administration of Disease Control and Prevention, proposed the overall epidemic prevention goals after policy adjustments: “The key risks that should be controlled must be controlled. Prevention and control measures that should be implemented must be implemented, and those that should be canceled must be resolutely cancelled." Limited prevention and control resources should be used on the most important prevention and control work, to protect people's life safety and health to the greatest extent, and to minimize the impact on people. The impact on the normal production and living order of the people.

According to data from the National Health Commission, from 0 to 24:00 on November 21, 31 provinces and the Xinjiang Production and Construction Corps reported 2,145 new local confirmed cases, 25,754 local asymptomatic infections, and 25,754 local asymptomatic infections. The number has exceeded 20,000 for seven consecutive days. At present, the epidemic situation in Guangdong, Chongqing, Henan, Gansu, Beijing and other places is relatively severe and is still on the rise.

A data expert who has been monitoring the trend of the new crown epidemic for a long time pointed out to "China News Weekly" that by mid-December, the national epidemic will be in a plateau period, and there may be a "double superposition of new crown and influenza" this winter and next spring. , which will put pressure on existing medical resources. Judging from the current situation, an infected person can infect 5 to 6 people on average every four days. We must still be wary of "super spreaders" that may appear in some high-density places.

Citizens are queuing up for nucleic acid testing. Picture/Visual China

How should the nucleic acid sampling points be laid out?

After the issuance of the "Twenty Measures", many places have experienced duplication in the setting up of nucleic acid testing points, and in some places many testing points have been withdrawn.

A person from the local Center for Disease Control and Prevention explained to China News Weekly that this kind of swing and repetition reflects the dislocation between the supply and demand of local nucleic acid testing. 48-hour or 72-hour nucleic acid testing is still required, which means the demand is still there, but after the partial abolition of nucleic acid sites, the supply has decreased.

As for the relevant requirements for nucleic acid inspection in public places, at the press conference of the Joint Prevention and Control Mechanism of the State Council on November 17, Shen Hongbing pointed out that people moving across regions need to show a 48-hour negative nucleic acid test to take a flight, High-speed rail, etc., people checking into hotels and tourist attractions need to check the health code and 72-hour nucleic acid.

Since the issuance of the "Twenty Measures", as the number of epidemics in some provinces and cities has increased, many regions have further tightened nucleic acid testing requirements, and have changed the nucleic acid testing requirements for entering shopping malls, supermarkets, office buildings and other places. 72 hours becomes 24 hours.

At 8:00 pm on November 20th, Guangzhou Zengcheng District issued a notice to strengthen social control for the first time since the current epidemic, requiring that from November 21st, the entire district will suspend dine-in meals, primary and secondary schools, and kindergartens. Offline teaching or returning to kindergartens is suspended. Personnel entering and exiting supermarkets, farmers' markets, communities and other places must present a 48-hour nucleic acid negative certificate.

At the press conference of the Joint Prevention and Control Mechanism of the State Council on November 17, a reporter asked: "Without carrying out nucleic acid testing for all employees, but still checking the nucleic acid test results, there have been cases of people lining up in many places." How to alleviate the contradiction between supply and demand of nucleic acid testing when there are long queues for nucleic acid testing?" Guo Yanhong, director of the Department of Medical Emergency Response of the National Health Commission, said that the layout of nucleic acid testing points is actually a normalized epidemic prevention and control. An arrangement is to facilitate the public to do all the inspections if they are willing and to do all the inspections if they should. Sampling points should cover the service population within the jurisdiction; sampling services should be provided at staggered peaks according to the needs of different groups; for communities and places with high population density and high flow of people, sampling should be expanded by adding sampling points and increasing sampling personnel. Provision of services, etc.

At a convenient nucleic acid testing point, staff scanned the QR code to register citizens who came for nucleic acid testing. Xinhua News Agency

On the other hand, Shen Hongbing, deputy director of the National Administration of Disease Control and Prevention, pointed out at a press conference on the 17th that when regular nucleic acid testing is carried out in areas where there is no epidemic, only risk positions and key personnel need to be tested. For nucleic acid testing, the scope of nucleic acid testing must not be expanded, and nucleic acid testing for all employees is generally not carried out according to administrative regions.

According to the latest "Implementation Measures for Nucleic Acid Testing for New Coronavirus Epidemic Prevention and Control" released on the 21st, specifically, this type of people who "should be tested and tested" mainly include two categories: one is high-risk groups, such as Medical staff, cross-border transportation drivers, cleaning staff, customs personnel, staff in centralized isolation areas, etc. are required to conduct a nucleic acid test once a day. The other category is key groups with high mobility, such as express delivery, takeout, hotel staff, decoration and loading workers, etc., which are required to carry out nucleic acid testing twice a week.

In addition, regular nucleic acid testing must also be carried out in key places such as schools, nursing homes, factories, hospitals, etc. That is, "after one or more local epidemic cases occur within the jurisdiction, a comprehensive nucleic acid test should be organized and completed in a timely manner." According to the test results and the risk of epidemic spread, nucleic acid testing can be carried out according to the sampling ratio of at least 20 per day or the testing requirements of the jurisdiction."

An unnamed public health expert pointed out to China News Weekly that the setting up of nucleic acid sites is superficially a matter of resource optimization, but more essentially is how to carry out normalized nucleic acid testing. The goal is to ensure effective and accurate monitoring of the epidemic while narrowing the scope and frequency of nucleic acid testing as much as possible. For example, in non-epidemic areas, if nucleic acid sampling is only for high-risk groups and key groups in the future, is it still necessary to set up sampling points in each community? If it is reduced, what density should be deployed?

The aforementioned local disease control officials believe that now, various regions can only make "limited adjustments" on issues such as how many nucleic acid sites should be set up and how to adjust the distribution, and then slowly explore in practice and make adjustments based on needs. Evaluate how many nucleic acid spots are more appropriate to retain. And this will be a dynamic adjustment process, "it may be collected and released, and if it is not enough, add a few more."

How to accurately organize nucleic acid testing?

At the beginning of the release of the "Twenty Articles", many experts believed that the most "burden reduction" for grassroots epidemic prevention was to make it clear for the first time that nucleic acid testing for all employees was generally not carried out according to administrative regions, but only for those infected. It is carried out when the source and chain of transmission are unclear, the community transmission time is long, and the bottom of the epidemic is unknown.

Experts point out that this correction comes at the right time. On the one hand, it is now difficult for the finances of many places to support rounds of nucleic acid tests for all employees, as evidenced by the fact that many places have recently begun to charge for nucleic acid tests; on the other hand, with the normalization of nucleic acid tests in the past period, some places have Nucleic acid testing has actually become inefficient or even ineffective.

However, with the recent emergence of large-scale epidemic clusters in many places across the country, the prevention and control situation in various places has become increasingly severe and complex, and many places have restarted a new round of regional full-scale nucleic acid testing.

Due to the severe epidemic situation, six districts in Guangzhou recently announced the launch of nucleic acid testing for all employees. On November 12, Chongqing announced that it would carry out nucleic acid testing for all employees in the central urban area and implement "one test per day" because of "the unknown source of infection, unclear transmission chain, and long community transmission time, etc."

A community in Haizhu District has been blocked. Photo source/China Economic Weekly Photography: He Yushuai

On November 12, Tieli, a county-level city at the southern foot of the Xiaoxing'an Mountains in Heilongjiang Province, found 1 In order to quickly block the spread of the epidemic and prevent spillover, the Tieli City Epidemic Prevention and Control Headquarters decided to implement a three-day temporary "silence" in the entire region starting from 0:00 on November 13, 2022: all urban and rural areas Residents are not allowed to go out outside of regional nucleic acid testing times. As of the 14th, 3 positive cases have been found in Tieli City, and as of the 21st, 16 positive cases have been found.

According to the latest "Implementation Measures for Nucleic Acid Testing for New Coronavirus Epidemic Prevention and Control", for provincial capital cities, cities with a population of more than 10 million and general cities, if the transmission chain is unclear, there are many risk places and risk people, When there is a high mobility of risk personnel and there is a risk of the epidemic spreading, a nucleic acid test for all employees must be carried out once a day. After three consecutive nucleic acid tests show no socially infected persons, another nucleic acid test for all employees must be carried out three days apart. Infected people can undergo nucleic acid testing for all employees. Moreover, the scope of nucleic acid testing for all employees is limited to the area where the epidemic is located.

The aforementioned local disease control personnel pointed out that according to policy requirements, the prerequisite for not requiring nucleic acid testing for all employees is that the local epidemic transmission chain is clear and the source can be traced in time, which is directly related to the local epidemic control capacity. But in fact, the level of epidemic control, virus tracking and traceability varies greatly across regions. For general medium-sized cities, especially for some counties that lack epidemic control capabilities, it is almost impossible to respond to the spread of Omicron in the short term. If we quickly figure out the chain of transmission and find the source, the result is likely to be social transmission, with multiple points blooming, and the nucleic acid test for all members of the region will have to be restarted.

She also pointed out that after the "Twenty Articles" no longer determine sub-close contacts, the pressure on grassroots flow control can be relieved to a certain extent. However, when a large-scale epidemic breaks out, the rising number of newly diagnosed patients every day and their The close contact is still a big pressure for the grassroots transfer teams. "The problem at the grassroots level is not only the lack of people, but also the lack of professional transfer personnel."

Shen Hongbing pointed out that nucleic acid testing is an important means for early detection of epidemics and an important prerequisite for assessing epidemic risks and taking timely measures to prevent the spread of the epidemic. All localities must organize and carry out nucleic acid testing scientifically and accurately based on the risk of the epidemic. "We can neither increase the number at any level nor reduce the number at will."

The accuracy of blockade and control may be further improved

Among the twenty optimization policies, in addition to the restrictions on nucleic acid for all employees, there are two adjustments that have a great impact on the epidemic prevention effect. : First, sub-close contacts will no longer be determined; second, the risk area will be redefined, the medium-risk area will be cancelled, and the scope of high-risk area closures will be reduced from communities to units and buildings.

The aforementioned local disease control personnel said that the delineation of risk areas used to be an area, but now it is a point. The scope of the closure and control is smaller, but the accuracy of the closure and control has improved. Disease control Personnel must delineate risk points based on the movement trajectories, living and working habits, and exposure conditions of the confirmed cases, which requires professional research and judgment. The final test is still the flow control ability of the grassroots level.

She said: “Recently, the National Health Commission’s Steering Group proposed when guiding local epidemic prevention work that the scope of containment may be further narrowed in the future. It will no longer be a unit, and may even be narrowed to the upper and lower parts of the infected person. Neighbors on both sides only need to close a few households.”

It is worth noting that in the latest “New Coronavirus Pneumonia Epidemic Risk Area Delimitation and Control Plan” released on November 21, the “Twenty Articles” were included. "A patch has been made" regarding the downgrade conditions for high-risk areas.

The "Twenty Articles" measures stipulate that if no new infections are found in high-risk areas for five consecutive days, they will be reduced to low-risk areas. However, the "Plan" further clarified: No new infections were found in the high-risk area for five consecutive days, and all personnel in the risk area completed a round of nucleic acid screening negative on the fifth day and were reduced to a low-risk area. Experts pointed out that this is to prevent some places from "one-size-fits-all" unblocking, which is equivalent to "installing a valve."

The "New Coronavirus Pneumonia Epidemic Home Isolation Medical Observation Guidelines" released on November 21 further clarified that the objects of home isolation include the following categories: special groups of close contacts, close contacts after the release of centralized isolation Contacts, arrivals, spillover personnel from high-risk areas, and other personnel who cannot be placed under centralized isolation medical observation after professional assessment.

Since the issuance of the "Twenty Measures", the pressure on communities to prevent and control has increased due to the shift of various groups of people, such as sub-contact and spillover personnel from high-risk areas, from centralized isolation to home isolation. Nucleic acid testing and risk area management pose challenges. “In the past, few people had to stay at home for quarantine, but now they have to stay at home except for close contact.” The aforementioned disease control person said with emotion.

A virologist pointed out to "China News Weekly" that home isolation needs to meet certain conditions, such as having a separate room, not using the bathroom and kitchen with people who do not live with you, and the household area cannot be larger than Too young, there should be no high-risk people living in the same household, etc. The community needs to first investigate whether the quarantined people meet the conditions for staying at home, and provide detailed education and guidance on home quarantine life, such as how to disinfect the bathroom after using it, how to avoid contact with family members, etc.

However, the aforementioned disease control sources revealed that because there are too many people who need to be quarantined at home in the short term, it is difficult for the community to have the energy to evaluate all family environments and then classify them for disposal. “As far as I understand, currently, home quarantine is Most of the people are self-reliant when it comes to supplies, and many family members are not shy during the quarantine period."

Another expert close to the Beijing Center for Disease Control and Prevention revealed to China News Weekly that home quarantine is very important. Medical staff are under great pressure because they need to go to their homes to do nucleic acid tests. Many experts have suggested that antigen testing can be supplemented during home isolation. It is required to detect nucleic acid and continuously self-test the antigen every day and report the results.

Author: Huo Siyi