html Since March, there has been a trend of concentrated outbreaks of new coronavirus local epidemics in many places across the country. As of the 13th, more than 10,000 cases of local infections have been reported across the country, affecting 27 provinces, showing the characteristics of many spots, wide coverage, and high frequency.
On March 11, 2022, at a nucleic acid testing sampling point in Dadong Street, Chuanying District, Jilin City, staff conducted nucleic acid testing samples for residents (Source: Xinhua News Agency)
According to the current situation, Jilin Province, Guangdong Province, and Shanghai City The epidemic is still developing, and the rate of increase is still very fast in some places. The epidemic transmission chain in various places is complex and the sources are different, and prevention and control policies are being stepped up.
" Life Times " interviews authoritative experts to explain in detail the issues of public concern during this epidemic and provide further guidance for current epidemic prevention.
Interviewed experts
Dean of Shenzhen Third People's Hospital (Second Affiliated Hospital of Southern University of Science and Technology) Lu Hongzhou
Chief physician and professor of the Department of Respiratory and Critical Care Medicine, Jiangsu Provincial People's Hospital Yin Kaisheng
Chief Physician of the Department of Respiratory and Infectious Diseases, Beijing You'an Hospital Affiliated to Capital Medical University Li Tongzeng
Associate Professor of Pathogen Biology, School of Basic Medicine, Fudan University Chen Jieliang
Author of this article | Life Times reporter Zhang Fang Gao Yang Niu Yulei Ren Linxian
Editor of this article | Ren Linxian
Omicron variant strains were detected in many places
Citizens conducted a round of nucleic acid testing
From March 1, there were 119 new cases of new coronavirus infection in the country, to March 13, there were 2,125 new cases. From the beginning, it only involved a few provinces and cities, to suddenly spreading to 27 provinces, it only took 12 days , this is a situation that has never occurred in the past.
Among the provinces with rapid growth in new local cases across the country, Jilin has the fastest growth. On March 13, Jilin Province reported 895 confirmed cases. Since this round of epidemic, the total number of confirmed cases in Jilin Province has exceeded 2,000. As of 14:00 on the 14th, there are still 3,868 people who are positive for the new coronavirus in preliminary screening and are waiting for clinical diagnosis.
Jilin Province’s 34th press conference on epidemic prevention and control stated that the source of this round of epidemic was the evolutionary branch of the Omicron variant BA.2, which was initially judged to have been imported into Jilin Province in late February and spread locally. Currently, Jilin City, Changchun City and other places have implemented closed management of all communities (villages) and units in the city, and are accelerating nucleic acid testing of all employees, racing against time to find out the bottom line of the epidemic.
Currently, three makeshift hospitals have been put into use in Jilin City, and three more are being built at the same time. There is also a makeshift hospital in Changchun City that is about to open.
Ms. Wang from Jilin City told the "Life Times" reporter that now citizens basically "do not go out unless necessary." In terms of daily life, in ordinary communities, one household can go out to buy food for 3 to 4 hours a day. In communities with epidemics, people are not allowed to go out. Food will be delivered to their doorsteps every day. "Now, everyone's most important daily task is to undergo nucleic acid testing over and over again. I have done it 7 times."
Mr. Zhang, who lives in Changchun City, is also cooperating with the city's nucleic acid testing. In the past 5 days, he has done it 4 times in total. nucleic acids. "It feels like I'm back to the beginning of 2020." Mr. Zhang's wife said that her son started taking online classes at home just one week after school started. Fortunately, she also works from home and can look after the children at home. Mr. Zhang's automobile company is a key enterprise in Changchun City and has not yet stopped work. When he went out in the past two days, he found that "many shops are closed, only supermarkets and pharmacies are still open, and there are almost no people on the road. It seems that the city has become empty overnight."”
According to the Shandong Provincial New Crown Pneumonia Epidemic Prevention and Control Work Conference, a total of 6 transmission chains have been found in the province in this round of epidemic, most of which occurred in crowded places such as schools and factories. The infection strain is the Omikeron variant BA .1.1 and B A.2, mainly the more contagious BA.2 evolutionary branch
Ms. Liu, who lives in Jimo District, Qingdao City, said that although schools in Qingdao have been closed, many enterprises and institutions are still working normally, and supermarkets are full of supplies. However, some business hours have been shortened, and some clothing stores with dense personnel The market has been closed. Some closed areas have implemented "area closure, stay at home, and door-to-door services." She also told reporters that Qingdao City is conducting nucleic acid testing for citizens in an orderly manner, but the progress is not uniform. Laixi City is the center of the Qingdao epidemic, and nucleic acid testing is more frequent there. l4
Mr. Li, who lives in Laixi City, revealed to a reporter from Life Times that Laixi received news as early as the evening of March 4 that there were three confirmed cases in the city. “The first round of nucleic acid testing began that night, and some confirmed cases were The community was under closed management, and in the early morning of the next day, the rule of 'stay away unless necessary' was notified. On March 10, we received a new notice stating “Don’t go out unless necessary.” Now, all communities and villages in the city have been closed down, and all work has stopped. In addition to going out to do nucleic acid tests, household material purchases rely on scanning QR codes to place orders and having people deliver them. "
As the local epidemic spreads in China, many places have made policy adjustments in response to the current prevention and control situation:
Since a cluster epidemic occurred in Dalang Town, Dongguan City on March 1, the epidemic situation in Guangdong Province has also seen a partial rebound. Now Shenzhen and Dongguan have issued new epidemic prevention measures: all non-essential movements are suspended, and those with special needs must leave the city with a negative nucleic acid certificate; city buses and subways are temporarily suspended; the city's communities and urban villages , industrial parks, etc. are subject to closed management
. On March 11, the Shanghai New Crown Pneumonia Epidemic Prevention and Control Leading Group Office announced the traceability results of recent local confirmed cases. The source of infection focused on: the virus carried by overseas imported cases contaminated the environment, and local infections were caused and spread due to management negligence. At present, Shanghai requires people not to leave Shanghai unless necessary. If you really need to leave Shanghai, you must submit a negative nucleic acid report within 48 hours; inter-provincial team travel and "air tickets + hotels" are suspended. Business; all passenger stations are suspended.
The new cases in Beijing are characterized by multiple channels and multiple transmission chains. The Beijing Center for Disease Control and Prevention has issued an initiative of "do not travel to Beijing unless necessary" and requires the continued implementation of "continue to Negative "Nucleic acid certificate + Beijing Health Treasure Green Code" return and arrival policy to Beijing.
Other provinces and cities have also strengthened the investigation of the movement of people in medium and high-risk areas, requiring people coming from and passing through medium- and high-risk areas to provide negative nucleic acid certificates, if necessary. Must be carried out as required Home quarantine and health monitoring.
Hidden spread increases the pressure of prevention and control.
This round of new crown epidemic has spread widely, is growing rapidly, and has some new characteristics. The public is concerned about There are also many questions. "Life Times" reporters interviewed experts to answer them one by one.
1 Why is the number of cases increasing so fast?
Chen Jieliang, associate professor and doctoral supervisor at the Department of Pathogen Biology, School of Basic Medical Sciences, Fudan University, said that the strains that have caused recent epidemics in Hong Kong, Shanghai, Jilin and other places are all Omicron BA.2 subtypes, which are more prevalent than the previously popular Omicron. The infectivity of Rong BA.1 has increased by about 30%, and the replication titer in bronchial tissue is 70 times that of the Delta variant, which makes the virus spread very quickly. The R0 value (basic infection number) of the original strain of the new coronavirus is 3~5, that is, one person infected with the new coronavirus can infect 3~5 people; the R0 value of the delta strain is 6~8; and the mystery The R0 value of the Kron strain has reached 10 or even 12.
Li Tong, chief physician of the Department of Respiratory and Infectious Diseases at Beijing You'an Hospital affiliated to Capital Medical University, once said that because the Omicron BA.2 subtype has the characteristics of immune escape, covert transmission, fast transmission speed, and strong transmissibility, if When community transmission occurs, the number of infected cases can double within two or three days. The confirmed case in Xi'an infected people who passed by him because of "a mouthful of sputum", which is enough to show how strong the spread of the virus is.
In addition, the epidemic has lasted for more than two years, and prevention and management in some places have been relaxed, resulting in omissions. In addition, infection with Omicron BA.2 subtype usually causes mild or asymptomatic symptoms. If the infected person does not take the initiative to see a doctor for screening, or if there is no pop-up window after purchasing medicine in the pharmacy, it will be difficult to detect. If these people carrying the virus continue to dine together, travel, and socialize, they may cause rapid spread over a large area.
2 People diagnosed in many places have mild symptoms, and the number of asymptomatic people detected even exceeds those diagnosed. What does this mean?
Li Tong once said that this has something to do with vaccination. Although vaccination cannot eliminate the possibility of an individual being infected with the virus, it can minimize the risk of severe disease. When the antibodies in the body inhibit the virulence of the virus, it will appear asymptomatic or mild.
Chen Jieliang believes that the large number of asymptomatic infections may be related to the weakened toxicity of the new mutant strain itself. Although Omicron does not infect the lungs as easily as previous strains and has fewer severe cases, it will replicate more in the upper respiratory tract and is more contagious, so it is still very harmful.
3 Is the epidemic in my country related to the "Delta Chron" variant of the new coronavirus?
French scientists have confirmed for the first time through genome sequencing that the "Delta Chron" variant of the new coronavirus does exist. Related cases have been reported in the United States and Europe. Is the epidemic in my country related to it?
Yin Kaisheng, chief physician and professor of the Department of Respiratory and Critical Care Medicine at Jiangsu Provincial People's Hospital, explained that the "Delta Chron" variant of the new coronavirus has not yet been detected in my country. It is undeniable that the emergence of virus variants is inevitable. If it does not bring about major changes in clinical disease characteristics, there is no need to worry too much. However, we must strengthen specialized, planned, and forward-looking research in advance to promptly discover the characteristics of relevant virus mutations and , so as to prepare for the subsequent fight against the epidemic.
4 Some areas without confirmed cases are conducting "full nucleic acid testing". Is this necessary?
Many citizens do not understand the city’s multiple rounds of nucleic acid testing that are being carried out in many places, and some even do not cooperate. Lu Hongzhou, director of the Shenzhen Third People’s Hospital (the Second Affiliated Hospital of Southern University of Science and Technology), said that the key to controlling the epidemic is to “early Discover". The reason why this round of epidemic has multiple concentrated outbreaks is related to the failure to detect imported cases as early as possible. Asymptomatic people do not get sick and are not detected, but they are still infected and can spread the virus. In this sense, asymptomatic people also need to be detected in time to avoid causing the epidemic to get out of control.
Chen Jieliang said that from the perspective of the virus, this round of epidemic spreads quickly and is highly concealed. There are a large number of asymptomatic infections, which brings great difficulties to group epidemic control and prevention and control, so many places have to adopt "closed" measures. The purpose of the upgraded prevention and control measures is to reduce social mobility and find out the bottom line, so as to achieve dynamic clearing as soon as possible and in a short period of time.
5 This epidemic occurred in the north and south at the same time. Does it mean that the new coronavirus is not affected by temperature and humidity?
Chen Jieliang introduced that viruses that infect the respiratory tract are generally more likely to invade in winter and spring when the climate is drier, and the virus can physically survive longer in cold environments.However, the new coronavirus exists in both the northern and southern hemispheres at the same time. Although the seasons in the northern and southern hemispheres are opposite, the epidemic has continued to spread, which suggests that the new coronavirus is not greatly affected by climate and temperature.
In addition to the seasonal impact of this epidemic, my country also has a special situation, that is, the Spring Festival brings population mobility, including imports from Hong Kong, overseas personnel returning to China for the holidays, etc., there may be the possibility of hidden imported cases, and then quietly occur in the community. It spread silently and fermented for a period of time. Multiple factors have caused the current situation.
6 Are the sequelae of COVID-19 serious?
A study published by Wuhan Union Hospital last year found that even non-severe patients had multi-system problems nearly a year after the diagnosis of COVID-19, such as physical symptoms such as difficulty sleeping, shortness of breath, fatigue and joint pain, as well as psychological problems such as anxiety and depression. . In addition, 56.7% of non-severe patients showed abnormal lung CT. Recently, research from the University of Oxford in the UK has found that the new coronavirus can cause patients' brain atrophy, loss of gray matter in areas that control emotions and memory, and damage areas that control the sense of smell.
In this regard, Yin Kaisheng said: "There is still relatively little data that can be used to prove the sequelae, and most of the research subjects are severe patients in the early stages of the epidemic. The number of confirmed cases in the United States is already large, but the actual research data on the sequelae is still insufficient. Therefore, the sequelae are not absent, but the extent of their impact remains to be discussed. From a clinical point of view, the sequelae of mild cases are indeed higher than those of severe cases. "There are few patients."
Chen Jieliang said that the sequelae of COVID-19 discovered so far are significantly different from those of influenza . The specific incidence rate of various symptoms is affected by various factors such as virus infection, genetic background, and individual differences. There is still a lack of relevant research in China, including Whether the long-term symptoms of COVID-19 will disappear, whether patients will recover, and how long the sequelae will last are all unanswered. What is relatively clear is that personal prevention, early diagnosis and early treatment after infection are of great significance to avoid the development of severe illness and serious sequelae.
7 Is the new crown vaccine still effective? Is sequential vaccination necessary?
Chen Jieliang said that there is currently sufficient and strong evidence that all types of new coronavirus vaccines can reduce the rate of severe illness and mortality. More than 90% of cases of severe illness and death are caused by people who have not been vaccinated, and the majority of them are older people with poor immunity. People who have not been vaccinated are 10 times more likely to develop severe illness than those who have been vaccinated. about.
Sequential vaccination refers to alternating vaccination between different technical routes or different dosage forms of the same vaccine. In layman's terms, COVID-19 vaccines with different technical paths are mixed in a certain order. For example, the first two injections are the inactivated vaccine , and the booster shot can be used to vaccinate the recombinant protein vaccine or the adenovirus vector vaccine.
Li Tong once said that sequential vaccination can further increase antibody levels on the basis of booster shots, but it still cannot guarantee complete freedom from infection.
8 Can antigen detection replace nucleic acid?
The Comprehensive Team of the Joint Prevention and Control Mechanism of the State Council recently decided to add antigen testing as a supplement to nucleic acid testing, and the public can purchase the test on their own. Can this antigen test replace nucleic acid?
Yin Kaisheng said that antigen testing is a supplement to nucleic acid testing. On the one hand, antigen testing is faster than nucleic acid testing. On the other hand, even non-professionals without equipment can use antigen testing by themselves, which is more convenient and cheaper.
Li Tong once said that the antigen can usually be detected within 5 days after the onset of symptoms; while the nucleic acid test can detect it when there are no symptoms, and it will be positive 1 to 2 weeks after the onset of the disease. The detection window time longer.However, antigen testing has value in many scenarios. For example, after an infected person is found in a community, all residents are organized to undergo nucleic acid testing. It will take a long time to wait for the results. If you do antigen testing, you can quickly get a feel for the community. It will help control the epidemic earlier.
In this round of epidemic, many schools have experienced cluster outbreaks. In this case, if antigen testing can be used as soon as possible, better control effects may be achieved.
Insist on dynamic clearing and put an end to "simultaneous interpretation of characters"
As the lethality of the new coronavirus is weakening, the saying that "the new coronavirus is more like a large flu" has spread, and many Western countries have adopted the "coexist with the virus" "Strategy, give up clearing.
However, on March 14, experts from the National Health Commission comprehensively judged that the current epidemic prevention and control in our country is generally based on the general strategy of "preventing external imports and preventing internal rebound" and the general policy of "dynamically clearing of " to cope with the epidemic. The Micron epidemic is completely effective, but due to the characteristics of Micron being highly concealed and spreading quickly, we need to take earlier, faster, stricter and more practical measures in the process of responding to the epidemic.
So, how should we respond to this epidemic? What new changes will occur in the future?
1. Dynamic clearing is still an important goal at the moment
Lu Hongzhou said that the reason why some European and American countries emphasize that they can coexist with the virus is because their so-called "low case fatality rate" is based on the death of a large number of severe cases, and now they remain The population has withstood a new coronavirus epidemic and has strong autoimmunity, so they rarely die. But the situation in our country is completely different. We have not experienced a national pandemic of the virus. Once we are "flat" and relaxed, the consequences and costs will be unbearable.
Li Tong once said that the new coronavirus does have the possibility of developing into a "large flu", but it is not possible yet because one of the prerequisites for it to become a "large flu" is that the effective vaccination rate is very high. Taking Hong Kong as an example, data disclosed by the Infectious Diseases Division of the Center for Health Protection shows that among the early deaths, the elderly accounted for the majority. The case fatality rate among vaccinated people was only 0.03%, and the case fatality rate among unvaccinated people was 0.54. %, the difference between the two is as high as 18 times. We currently have no precise statistics on the vaccination rate of booster shots, so we must not relax our vigilance and still insist on dynamic clearing.
2. The elderly and children must be vaccinated as soon as possible, and high-risk groups should receive booster shots.
Chen Jieliang said that the primary goal of epidemic prevention and control is to prevent large-scale outbreaks and do not want medical runs and a large number of severe cases to occur. The virus spreads extremely fast, and even if its virulence weakens, it can still easily cause a large number of deaths and severe cases. Therefore, our country should continue to prepare sufficient medical reserves, further establish population immunity barriers, implement a precise prevention and control system, accumulate small victories into big victories, and eventually reach an open and balanced state naturally.
It is recommended that people who have already received two doses of inactivated vaccine can consider taking another booster shot of inactivated vaccine, or take them sequentially. High-risk groups, including the elderly and young children, must complete the COVID-19 vaccination as soon as possible.
3. Take precautions to avoid "simultaneous interpretation of characters"
The source of the recent epidemic in Hangzhou points to contaminated overseas items. Chen Jieliang said that laboratory data shows that the virus can survive on the surface of objects for about 3 days under normal temperature conditions, and can survive longer in the cold chain. Although the country has a series of prevention and control disinfection procedures for logistics package handling, individuals must pay special attention when receiving packages, especially packages from high-risk areas at home and abroad. They must first use 75% alcohol or disinfectant for surface disinfection. , try to unpack outdoors when unpacking, and wash your hands promptly after unpacking.
(Drawing: Xi Yue)
Lu Hongzhou said that facts have proven that all the prevention and control measures we have adopted so far are still effective against the current strain, so the discovery of the epidemic is an "inflection point." As long as overseas imports are strictly controlled and the original prevention and control measures are implemented on this basis, I believe that this round of epidemic can be controlled soon.
Yin Kaisheng said that this epidemic has many points, a wide range of areas and a large volume, and it will take one to one and a half months to control it. There will be a growth period of 10 to 15 days in the early stage of the epidemic, and then there will be an inflection point, and the number of confirmed cases will gradually begin to decrease. After 1 to 2 months, it is expected to be basically under control around the May Day holiday.
Chen Jieliang has a more optimistic view. He believes that strong epidemic prevention and control measures have been adopted in various places. The current main goal is to reduce the spread of the virus among the population and block the chain of transmission. It is expected that prevention and control will be seen in about two weeks. Effect.
Li Tong once said that although the situation of epidemic prevention and control is not optimistic, people do not need to completely give up traveling or suspend their life and work. As long as local policies allow, you can live and travel safely by abiding by epidemic prevention regulations, taking personal protection, wearing masks, not having gatherings, and washing hands frequently. ▲
Editor of this issue: Deng Yu
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