Since March, there has been a trend of concentrated outbreaks of the new crown local epidemic in many parts of the country, and as of the 13th, more than 10,000 cases of local infection have been reported nationwide, affecting 27 provinces, showing the characteristics of many points, wide coverage and large frequency.
On March 11, 2022, at a nucleic acid test sampling point in Dadong Street, Chuanying District, Jilin City, staff conducted nucleic acid testing and sampling for residents (Source: Xinhua News Agency)
According to the current situation, the epidemic situation in Jilin Province, Guangdong Province and Shanghai Is still developing, and the speed of rise in some places is still very fast. The chain of epidemic transmission in various places is complex, the source is not the same, and the prevention and control policies are increasing.
"Life Times" (search for "LT0385" in WeChat to pay attention) interviewed authoritative experts to explain the public concerns of the current round of epidemic and give further guidance for the current epidemic prevention.
Experts interviewed
Lu Hongzhou, President of the Third People's Hospital of Shenzhen (the Second Affiliated Hospital of Southern University of Science and Technology).
Professor Yin Kaisheng, Chief Physician and Professor of the Department of Respiratory and Critical Care Medicine, Jiangsu Provincial People's Hospital
Li Tongzeng, chief physician of the Department of Respiratory and Infectious Diseases of Beijing You'an Hospital affiliated to Capital Medical University
Jieliang Chen, Associate Professor, Department of Pathogenic Biology, School of Basic Medical Sciences, Fudan University
This article is written by | Life Times reporter Zhang Fang Gao Yang Niu Yulei Ren Linxian
This article was edited | Ren Linxian
The Aumechjong variant was detected in many places
Citizens test nucleic acids round by round
From 119 new cases of new coronavirus infection in the country on March 1 to 2125 new cases on March 13, from only a few provinces and cities at the beginning to 27 provinces and cities at once, it took only 12 days, which is a situation that has never occurred before.
Among the provinces with rapid growth in new local cases in the country, Jilin has grown the fastest. On 13 March, Jilin Province reported 895 confirmed cases. Since the current round of the epidemic, the total number of confirmed cases in Jilin Province has exceeded 2,000, and as of 14:00 on the 14th, there are 3,868 cases of positive people with initial screening of the new crown virus waiting for clinical diagnosis.
According to the news of the 34th press conference on epidemic prevention and control in Jilin Province, the source of this round of epidemic is the evolutionary branch of the Aomi Kerong mutant strain BA.2, and the preliminary judgment is that it was imported into Jilin Province in late February and spread locally. At present, Jilin City, Changchun City and other places have implemented closed management of the city's communities (villages) and units, and are speeding up the nucleic acid testing of all employees and racing against time to find out the bottom of the epidemic.
At present, 3 cabin hospitals have been put into use in Jilin City, and 3 additional hospitals are also being built, and a cabin hospital in Changchun City is about to open.
Ms. Wang of Jilin City told the Life Times that citizens now basically "do not go out unless necessary." In terms of life, ordinary communities can go out for 3 to 4 hours a day to purchase food, and communities with epidemics are not allowed to go out, and someone will deliver food to their doorstep every day. "Now, the most important daily task for everyone is to get nucleic acid testing over and over again, and I've done it 7 times."
Mr. Zhang, who lives in Changchun City, is also cooperating with the city's nucleic acid testing, and in the past 5 days, he has done a total of 4 nucleic acids. "It feels like it's back in early 2020." Mr. Zhang's wife said that her son began to take online classes at home just a week after the start of school, but fortunately, she also works from home and can watch her children at home. Mr. Zhang's automobile company is a key enterprise in Changchun City, which has not yet stopped work, and in the past two days, he found that "many shops have closed, only supermarkets and pharmacies are still open, and there is basically no one on the road, as if the city was empty overnight." ”
According to the news of the press conference on the prevention and control of the new crown pneumonia epidemic in Shandong Province, a total of 6 transmission chains have been found in the province in this round of epidemic, mostly in schools, factories and other crowded places, and the infected strains are the Omi kerong mutant strains BA.1.1 and BA.2, which are mainly the more contagious BA.2 evolutionary branches.
Ms. Liu, who lives in Jimo District, Qingdao City, said that although schools in Qingdao have been suspended, many enterprises and institutions are still working normally, and the supermarket is full of materials, but the business hours have been shortened, and some of the densely populated clothing markets have closed. Some sealing and control areas implement "regional closure, staying at home, and providing door-to-door service". She also told reporters that Qingdao city is carrying out nucleic acid testing for citizens in an orderly manner, but the progress is not uniform, and Laixi City, located in the north of Qingdao City, is the center of the epidemic in Qingdao, where nucleic acid testing is more frequent.
Mr. Li, who lives in Laixi City, revealed to the "Life Times" reporter that Laixi first reported that there were 3 confirmed cases in the city on the evening of March 4, "the first round of nucleic acid testing began that night, and some communities with confirmed cases implemented closed management, and the provisions of 'non-essential do not leave Lai' were notified in the early morning of the next day." On March 10, we received a new notice that we wouldn't go out or visit unless necessary. Now, the city's communities, villages have been closed, the work has all stopped, in addition to doing nucleic acid out, family material procurement is relying on scanning the code to place orders, special delivery. ”
With the spread of the epidemic in China, many places have made policy adjustments to the current prevention and control situation:
Since the outbreak of the cluster epidemic in Dalang Town, Dongguan City on March 1, the epidemic situation in Guangdong Province has also rebounded locally, and now Shenzhen City and Dongguan City have issued new epidemic prevention measures: suspending all non-essential flows, and if there is a special need, they need to leave the city with a negative nucleic acid certificate; the city's buses and subways are temporarily suspended; and the city's communities, urban villages, industrial parks, etc. are closed and managed.
On March 11, the Office of the Shanghai Municipal Leading Group for the Prevention and Control of the Novel Coronavirus Pneumonia Epidemic announced the results of the recent traceability of local confirmed cases, focusing on the source of infection: the virus carried by imported cases from abroad polluted the environment, and due to management negligence, local infections caused and led to transmission. At present, Shanghai requires non-essential not to leave Shanghai, and if it is necessary to leave Shanghai, it must hold a 48-hour nucleic acid negative report; suspend inter-provincial group travel and "air ticket + hotel" business; and suspend all passenger terminals.
The new cases in Beijing have shown the characteristics of multi-channel and multi-transmission chain, and the Beijing Municipal Center for Disease Control and Prevention has issued an initiative of "non-essential not going out of Beijing" to this end, requiring the continued implementation of the policy of returning to Beijing and arriving in Beijing with a negative nucleic acid certificate + Beijing health treasure green code.
Other provinces and cities have also stepped up screening of the movement of people in medium- and high-risk areas, requiring people from and passing through medium- and high-risk areas to provide negative nucleic acid certificates, and if necessary, home isolation and health monitoring as required.
Hidden transmission increases the pressure of prevention and control
The current round of the new crown epidemic has a wide range of impact, rapid growth, and some new characteristics, and the public has many questions about it, and the reporter of Life Times interviewed experts to answer them one by one.
1
Why is the number of cases growing so fast?
Chen Jieliang, associate professor and doctoral supervisor of the Department of Pathogenic Biology of Fudan University's Basic Medical College, said that the strains that have recently caused epidemics in Hong Kong, Shanghai, Jilin and other places are all subtypes of Aomi Kerong BA.2, which is about 30% more infectious than the previously popular Aomi Kerong BA.1, and the replication titer in bronchial tissue is 70 times that of the Delta variant, which makes the virus spread rapidly. The R0 value (basic number of infections) of the original strain of the new coronavirus is 3 to 5, that is, one person infected with the new crown virus can be transmitted to 3 to 5 people; the R0 value of the Delta strain is 6 to 8; and the R0 value of the Aumechjong strain has reached 10, or even 12.
Li Tong, chief physician of the Department of Respiratory and Infectious Diseases of Beijing You'an Hospital affiliated to Capital Medical University, once said that because the Aomi Kerong BA.2 subtype has the characteristics of immune escape, hidden transmission, fast transmission speed and strong transmission, if there is community transmission, the number of infected cases can double within two or three days. The confirmed person in Xi'an City infected the person who passed by him because of "one mouthful of phlegm", which is enough to show how strong the virus is.
In addition, the epidemic has lasted for more than two years, and the prevention and management in some places has been relaxed, resulting in omissions. Coupled with infection with the Omikejong BA.2 subtype, the symptoms are usually mild or asymptomatic, and it is difficult to detect if the infected person does not actively seek medical screening, or does not come out of the pop-up window after purchasing drugs in pharmacies. These people who carry the virus continue to eat together, travel, and socialize, which may cause a large area of rapid transmission.
2
What does it mean that many people with confirmed cases are mild, and the number of asymptomatic people detected is even more than that of confirmed cases.
Li Tong once said that this has something to do with vaccination. Although vaccination cannot cut off the possibility of individual infection with the virus, it can minimize the risk of severe illness, and when 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 infected people may be related to the weakening of the toxicity of the new mutated strain itself. Although Omikejong does not infect the lungs as easily as the previous strain, and the number of severe cases is reduced, it will replicate more in the upper respiratory tract, be more contagious, and still be very harmful.
3
Is the epidemic in the mainland related to the "Delta Kerong" variant of the new crown virus?
French scientists have confirmed for the first time through genome sequencing that the new coronavirus "Delta Kerong" variant does exist, and related cases have been reported in the United States and Europe.
Professor Yin Kaisheng, chief physician and professor of the Department of Respiratory and Critical Care Medicine of Jiangsu Provincial People's Hospital, explained that at present, the mainland has not yet detected the "Delta Kerong" variant of the new crown virus. It is undeniable that the emergence of viral variants is inevitable, and there is no need to worry too much if there is no major change in the characteristics of clinical disease. However, we must strengthen specialized, planned and prospective research in advance, timely discover the characteristics of relevant virus mutations, and prepare for the follow-up fight against the epidemic.
4
Some areas without confirmed cases are "full nucleic acid", is it necessary to do so?
For the multi-round nucleic acid testing in the city that is being carried out in many places, many citizens do not understand, and some even do not cooperate, Lu Hongzhou, president of the Third People's Hospital of Shenzhen (the Second Affiliated Hospital of Southern University of Science and Technology), said that the key to controlling the epidemic is "early detection". The reason why there are multiple concentrated outbreaks in this round of the epidemic is related to the lack of early detection of imported cases from abroad. Asymptomatic people do not develop the disease and are not detected, but they are also infected with the virus and can also 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, the current round of epidemic spread fast, strong concealment, there are a large number of asymptomatic infected people, to the group circulation and prevention and control of great difficulties, so many places have to take "closed" and "full-staff" upgraded prevention and control measures, the purpose is to reduce social mobility, find out the bottom number, in order to achieve dynamic clearance in a short period of time as soon as possible.
5
Does the fact that the outbreak occurs in both the north and the south mean that the new crown virus is not affected by temperature and humidity?
Chen Jieliang introduced that viruses infecting the respiratory tract are generally more likely to invade in winter and spring, when the climate is drier, and the virus physically survives longer in cold environments. However, the coronavirus exists at the same time in the northern and southern hemispheres, and although the northern and southern hemispheres have reversed seasons, the epidemic has been circulating non-stop, suggesting that the new crown virus is not affected by climate and temperature.
In addition to the seasonal impact of the epidemic, there is also a special situation in the mainland, that is, the Spring Festival brings population movement, including hong Kong imports, overseas personnel returning to China for the festival, etc., there may be the possibility of hidden imported cases, and then there is a quiet spread in the community, after a period of fermentation, multiple factors have caused the current situation.
6
Are the sequelae of the new crown serious?
Wuhan Union Medical College Hospital published a study last year that found that even non-critical patients, nearly a year after the diagnosis of the new crown, there are multi-system problems, such as difficulty sleeping, shortness of breath, fatigue and joint pain and other physical symptoms, as well as anxiety, depression and other psychological problems. In addition, 56.7% of non-critically ill patients showed abnormal lung CT. Recently, research from the University of Oxford in the United Kingdom has found that the new crown virus can cause the brain of patients to shrink, lose gray matter in areas that control emotions and memory, and damage areas that control smell.
In this regard, Yin Kaisheng said: "At present, the data that can be used to prove the sequelae is still relatively small, and most of the research objects are serious patients in the early stage of the epidemic. The number of confirmed cases in the United States is already very large, but there is still not much research data on sequelae. Therefore, the sequelae are not absent, but the extent of their impact is still debatable. From a clinical point of view, patients with mild disease do have fewer sequelae than patients with severe disease. ”
Chen Jieliang said that the current discovery of new crown sequelae and influenza is significantly different, the specific incidence of various symptoms is affected by virus infection, genetic background and individual differences and other factors, there is still a lack of relevant research in China, including whether the long-term symptoms of the new crown will disappear, whether patients will be cured, how long the sequelae last, these questions have not yet been answered. It is more clear that personal prevention, as well as early diagnosis and treatment after infection, are of great significance to avoid the development of severe diseases and serious sequelae.
7
Is the COVID-19 vaccine still effective? Is it necessary to vaccinate sequentially?
Chen Jieliang said that there is sufficient strong evidence that all kinds of new crown vaccines can reduce the rate of severe illness and case fatality. In the case of severe illness and death, more than 90% are unvaccinated, mainly elderly and immune-poor people, and the probability of unvaccinated people developing severe illness is about 10 times higher than that of those who have been vaccinated.
Sequential vaccination refers to the alternating vaccination between different technical routes or different dosage forms of the same vaccine. In layman's terms, it is that the new crown vaccines of different technical paths are mixed in a certain order, such as the first two injections of inactivated vaccines, and the reinforced injections can be vaccinated with recombinant protein vaccines or adenovirus vector vaccines.
Li Tong once said that sequential vaccination can further increase the level of antibodies on the basis of strengthening the needle, but it is still impossible to guarantee that there will be no infection at all.
8
Can antigen testing replace nucleic acids?
The Comprehensive Group 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 masses can purchase tests on their own. Can this antigen test replace nucleic acids?
Yin Kaisheng said that antigen testing is a supplement to nucleic acid testing. On the one hand, antigen detection is faster than nucleic acid testing. On the other hand, even non-professionals who do not have the instrument can use antigen detection on their own, which is more convenient and less costly.
Li Tong once said that antigens can usually be detected within 5 days after the onset of symptoms; while nucleic acid tests can be detected when there is no symptom, and they are positive for 1 to 2 weeks after the onset of the disease, and the detection window is longer. However, antigen detection has use value in many scenarios, for example, after the discovery of infected people in the community, organize all residents to conduct nucleic acid testing, wait for the results for a long time, if the antigen test is done, you can quickly find the bottom in the community, which is conducive to early control of the epidemic.
In this round of the epidemic, many schools have clustered outbreaks, in this case, if the antigen test can be used in the first time, it may be possible to achieve better control effects.
Adhere to dynamic zeroing and eliminate "character simultaneous interpretation"
As the lethality of the new crown virus is weakening, the saying that "the new crown is more like a large flu" has spread, and many Western countries have adopted the strategy of "coexisting with the virus" and abandoned zero clearance.
However, on March 14, experts from the National Health Commission comprehensively judged that at present, the overall epidemic prevention and control of our country, the general strategy of "external prevention of import, internal prevention and rebound", the general policy of "dynamic clearance", and the response to the epidemic situation of Aumeikjong are completely effective, but due to the characteristics of strong concealment and rapid spread of Omicron, 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 emerge in the future?
1. Dynamic zeroing is still an important goal at present
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 fact that a large number of severe cases have died, and now the remaining population has carried through a round of the new crown virus epidemic, and their autoimmunity is strong, so they rarely die. But the situation on the mainland is completely different, we have not experienced a national pandemic of the virus, and once the "lying flat" is released, the consequences and costs will be unbearable.
Li Tong has said that the new crown virus does have the possibility of developing into a "big flu", but it is not yet possible, because one of the prerequisites for it to become a "big flu" is that the effective vaccination rate is very high. Taking Hong Kong as an example, the data disclosed by the Infectious Diseases Division of the Center for Health Protection show that the elderly account for the majority of previous deaths, of which the case fatality rate of the vaccinated population is only 0.03%, and the case fatality rate of the unvaccinated population is 0.54%, the difference between the two is as high as 18 times. We do not yet have accurate statistics on the vaccination rate of the booster needle, so we must not let our vigilance down, and we must still insist on dynamic clearance.
2. The elderly and children must be vaccinated as soon as possible, and the high-risk groups should be vaccinated with reinforcing needles
Chen Jieliang said that the primary goal of epidemic prevention and control is that there can be no large-scale outbreak, and there is no medical run and a large number of severe cases. The virus spreads extremely quickly, and even if the virulence weakens, it is still very easy to cause a large number of deaths and severe cases. Therefore, the mainland should continue to make sufficient medical reserves, further establish a population immune barrier, implement a precise prevention and control system, accumulate small victories into big victories, and eventually may naturally reach a state of open balance.
It is recommended that people who have been given two doses of inactivated vaccine can consider another dose of inactivated vaccine booster, or sequential vaccination. High-risk groups, including the elderly and young children, need to complete COVID-19 vaccination as soon as possible.
3. Do a good job of protection to avoid "character simultaneous interpretation"
The recent outbreak in Hangzhou was directed at contaminated foreign goods. Chen Jieliang said that laboratory data show that the virus can survive on the surface of the object for about 3 days under normal temperature conditions, and the cold chain can survive longer. Although the state has a series of prevention and control disinfection procedures in logistics parcel processing, individuals should also pay special attention when receiving packages, especially packages from high-risk areas at home and abroad, they should first use 75% alcohol or disinfectant for surface disinfection, unpack as much as possible outdoors when unpacking, and wash their hands in time after dismantling.
(Draft: Xi Yue)
Lu Hongzhou said that the facts have proved 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 the import of overseas is strictly controlled, and the original prevention and control measures are put in place on this basis, it is believed that the current round of epidemic will soon be controlled.
Yin Kaisheng said that the epidemic has many points, wide coverage and large volume, and it will take a month to control it in a month to a half. There will be a 10-15-day growth period in the early stage of the outbreak, and then there will be an inflection point, and the number of confirmed cases will gradually begin to decrease, and after 1 to 2 months, it is expected that it will be basically controllable around the "May Day".
Chen Jieliang is more optimistic, he believes that at present, various localities have taken strong epidemic prevention and control measures, the current main goal is to reduce the speed of transmission of the virus in the population, block the chain of transmission, it is expected to see the prevention and control effect in about two weeks.
Li Tong once said that although the epidemic prevention and control situation cannot be optimistic, people do not have to completely give up travel or life and work suspension. If local policies allow, it is also safe to live and travel safely by abiding by epidemic prevention regulations, doing a good job of personal protection, wearing masks, not eating together, and washing hands frequently. ▲
Editor of this issue: Deng Yu