[Global Times reporter Fan Wei, Chen Qingqing, Cao Siqi] The new crown pneumonia epidemic has disrupted the normal life of people around the world for two consecutive years, and how to completely end the pandemic has become an increasingly strong expectation in people's hearts. Recently, some studies from abroad have continuously conveyed such a voice - "The characteristics of strong transmission but weak toxicity of Omi kerong have shown a trend of 'influenzaization', and the harm caused by the new crown virus to all mankind seems to be gradually decreasing." Is there reason for optimism about ending COVID-19 once and for all in the near future? On related issues, the Global Times reporter recently interviewed Wu Zunyou, chief expert of epidemiology at the Chinese Center for Disease Control and Prevention.
"Omi kerong can't be a 'big flu'"
Global Times: There is now a voice in foreign countries that believes that Omilton has strong transmission but weak pathogenicity, and it is more and more like a "big flu". What do you think about that?
Wu Zunyou: Omi Kerong cannot be a "big flu", because the site of its infection is not the same as the flu, and the severity of the clinical symptoms it causes and the flu are completely two levels. The site of infection of the influenza virus is the upper respiratory tract, while the site of infection of the new crown virus is the lower respiratory tract. Upper respiratory tract infections rarely cause pneumonia, unless the disease is not treated for a long time, dragging on for a long time, in which case a small number of patients can cause pneumonia. Most people with lower respiratory tract infections develop pneumonia, including infection with the Omiljun strain. Previous data from Tianjin showed that of the 361 cases of infection, 42% of the infected people had symptoms of pneumonia of varying degrees, which is already a high proportion.
Such a high proportion of pneumonia patients, if it were not for the protective effect of our vaccines, the severity of the patient's condition would be much greater. Because after the vaccine is "bottomed", the infected person has a certain degree of immunity, so the symptoms will be much lighter. In addition, the response in our country is relatively fast, when the patient has just been diagnosed with no symptoms, or only mild disease, all cases will be hospitalized, which is different from European and American countries. In foreign countries, if there are no symptoms or mild symptoms, hospitalization will not be arranged at all. That's why our country has had almost no deaths since the outbreak in Beijing in June 2020 – because we treated early.
Looking at the world, the proportion of pneumonia caused by Omikerong is relatively high, except for China, the severe illness rate and case fatality rate caused by Omikejong in other countries are much higher than those caused by influenza. In the United States, for example, the number of deaths caused by the Omicron strain during its epidemic is even much higher than that caused during the Delta strain epidemic. The proportion of deaths caused by influenza is still relatively small. So Omiljung can't be a "big flu." If it is regarded as a "big flu", it will dilute the epidemic situation, weaken people's attention to it, and be very unfavorable to epidemic prevention and control.
Global Times: On January 19, The Lancet, a top medical academic journal, published a paper by Murray, director of the Institute for Health Metrics and Evaluation (IHME) at the University of Washington. The paper predicts that the global pandemic of the new crown virus is coming to an end and That March will be a key point in time. What do you think of this view?
Wu Zunyou: I think the views expressed in this paper are not very accurate. The author of the paper is a statistician and a top global expert in the field of mathematical models, who is not particularly well aware of biology and viruses. He based this hypothesis on the basis of the flu — if the previous flu could end within two years, then the new crown has been circulating for two years, and it should be time to end. He based his analysis on this logic, but because the flu and COVID-19 are so different, there are some places to accept the challenge of reality in this hypothesis. The first is that the immunity maintenance time after infection with influenza can usually reach one year, while the immunity maintenance time after infection with the new crown is generally about 3 to 6 months. The second is that the new crown virus mutates very quickly, almost every day. The mutation of influenza virus is regular, and the mutation cycle is long, usually changing every year or several years, in this year or several years, if the mutation of the virus is only in the "subtype", it will not affect cross-protection. Therefore, from the characteristics of virus mutation and from the law of the two-year epidemic of the new crown epidemic, the view that "March has become the key time point for the end of the world pandemic of the new crown epidemic" is not sufficiently based on science.
"The trend of the coronavirus epidemic is sure to weaken"
GLOBAL TIMES: What about your judgment?
Wu Zunyou: The trend of the new crown virus epidemic will definitely weaken in the coming period, because the epidemic of each new strain will always decline after reaching its peak, and the downward trend of Omilon has begun to show a downward trend in South Africa, and there are also signs of decline after a period of epidemic in other countries. For example, after the Delta strain pandemic in India in April and May last year, there was a period of time at a low epidemic level, and we were still studying why the epidemic in India suddenly decreased, and now after the fourth wave of the epidemic, the epidemic in India has risen again. Another example is Japan, during the Tokyo Olympic Games last year, the epidemic was more serious, but after the Olympic Games, the epidemic suddenly showed a sharp downward trend, and we also tried to explain why the epidemic in Japan suddenly subsided, however, when the fourth wave of the epidemic struck the world, the epidemic in Japan suddenly rose again. The new crown virus presents such an epidemic law, it will inevitably decline after a wave of epidemic peaks, so from a global perspective, the epidemic trend weakens in March or for some time to come, this possibility exists, and this possibility is very large.
The global covid-19 pandemic is contributed by several important factors, one is that the winter is more suitable for the survival and spread of the new crown virus; the second is that there are more winter festivals, Thanksgiving, Christmas and New Year, people will gather, and when the winter passes, people return to work, and the factors promoting the epidemic will be reduced; the third factor is that the mutated strain of Aomi Kerong is more contagious, especially those who have been infected or vaccinated in the past will also be infected and spread.
Global Times: There is a view that according to the characteristics of virus evolution, the stronger the spread of the virus, the weaker its toxicity, the weaker the pathogenicity, and in the end it will show the situation of "the end of the crossbow" until it is harmoniously coexisting with the host.
Wu Zunyou: This view confuses several issues. The contagiousness and pathogenicity of the new crown virus are not necessarily related biologically, and it is more of a sociological point of view. In my personal understanding, the more contagious and less pathogenic this inverse relationship is, the more social factors. Take the three respiratory infectious diseases of the new crown virus, SARS and Middle East respiratory syndrome as an example, they are all coronaviruses, but the case fatality rate is completely different. The case fatality rate of the new crown is less than 2%, the case fatality rate of SARS is about 10%, and the case fatality rate of the Middle East respiratory syndrome is about 34%, which is the lowest case fatality rate of the three coronaviruses, and it has the greatest impact on humans.
Why is this happening? Mainly because if the patient's symptoms are relatively mild, it is not easy to go to the doctor, just like the Aomi Kerong we talked about earlier, it causes patients with mild symptoms to be not easy to go to the doctor, but it is easier to infect the family and the society. However, if there is a severe situation after infection, the patient will soon go to the hospital, and the chance of the virus being transmitted to others will naturally decrease, and the infectivity of the virus will be weakened. Contagiousness is related to people's social behavior, the more frequent the communication, the more dense the population, the more contagious, and the severity of the disease will limit the ability of patients and society to interact.
Therefore, the statement that "the stronger the spread, the weaker its toxicity, the weaker the pathogenicity" is basically impossible to achieve biologically, and it is more from a sociological point of view of such a problem. I personally don't think that the new crown epidemic will eventually show this trend, the mutation of the new crown virus, at least so far has not seen this kind of law, will it appear in the future? I think this view may be overly optimistic.
"To deal with the new crown virus, we must adopt an integrated approach"
Global Times: The new crown virus can not only infect humans, but also spread among animals, so there is a view that humans may never be able to completely end the new crown epidemic and will coexist with the virus for a long time.
Wu Zunyou: This issue should be expressed at two levels. The first is that COVID-19 coexists with humanity, which now seems to be permanent. The second is that the severity and scale of the COVID-19 epidemic will depend on the extent to which humans are fighting COVID-19. It should be said that the new crown virus will always exist, but the epidemic level will be different.
What is difficult to determine now is whether it maintains a high level of epidemic as it is currently, which continues to affect people's lives and socio-economic development, or whether it can be controlled at the level of endemic infectious diseases through human wisdom and the use of science and technology, and no longer affect people's life and work and social activities. It is difficult for us to determine the extent of the future COVID-19 epidemic, which depends on the level of our scientific understanding of COVID-19 and the technical level and ability of human beings to prevent and control the epidemic.
Global Times: In recent times, in the outbreak of many outbreaks in the mainland, the infected people are basically mild and asymptomatic infected people, why is this happening?
Wu Zunyou: The recent increase in mild and asymptomatic infections has two reasons, one of which is that the symptoms of the infected people in Omilon may be relatively mild, but whether they are infected with Omilon or The Delta strain, the symptoms of infected people are relatively mild, which is due to the vaccination in the mainland, in 70% to 80% of the vaccinated population has developed a certain immunity, although this immunity can not completely prevent infection, but the symptoms of the infected people are greatly reduced, or do not show symptoms at all.
The increase in asymptomatic infections does increase the difficulty of prevention and control, because it is even more difficult to sort out the chain of transmission after the outbreak is discovered. However, it should be noted that the role of vaccines in controlling the epidemic is enormous, the symptoms of infected people are alleviated, and the number of cases that require medical care or have severe, critical or even deaths is greatly reduced, which also reduces the burden of medical treatment. So vaccines are still our biggest "weapon" to control COVID-19, including Omiljung.
Global Times: The relevant WHO spokesperson said in response to an inquiry from the Global Times reporter on January 24 that when the global vaccination rate reaches 70%, it means that the most critical period of the pandemic has passed.
Wu Zunyou: At present, it seems that WHO's statement is debatable. Before the fourth wave of the COVID-19 pandemic, the two-shot vaccination rate in most European countries, including Germany, France and the United Kingdom, had exceeded 70%, and the overall vaccination rate in the United States was also above 70%. There is a problem here. Originally, the concept of herd immunity achieved by vaccination was challenged after the emergence of Omi kerong, because of the occurrence of breakthrough cases.
If most of the mutant strains of COVID-19 have immune escape ability, this method is no longer applicable if the herd immunity is achieved by vaccination and thus ended the COVID-19 pandemic. So "70% of the vaccination rate means that the most critical period of the pandemic has passed" Itself is problematic, our country has reached 70%, but as long as there is a virus with escape, it will still be infected, most of the cases infected by this round of Tianjin epidemic are vaccinated, and the vaccine only makes the symptoms of the infected people milder. It is no longer possible to use an indicator such as vaccination rates to set a timeline for the termination of the COVID-19 pandemic, because it is complex and there is no single way to control covid-19. Now through a comprehensive approach, vaccines are undoubtedly the most important heavy weapon against covid-19, including Omilon. There are also strict public health measures, good personal hygiene habits, timely medical intervention, integration of traditional Chinese and Western medicine, prevention and treatment of these means of comprehensive application can control the new crown pandemic.
"'Dynamic zeroing' is by far the best way to prevent and control"
Global Times: Foreign media have been trying to attack China's "dynamic zeroing" policy from various angles, why is it that China's "dynamic zeroing" is still the best way to deal with the epidemic? If the current "dynamic zeroing" were to be adjusted, what criteria might be relied upon?
Wu Zunyou: In fact, China's "dynamic zero clearance" policy has made the epidemic in China hundreds of times lower than the world average. At present, there are many people who have lost their lives due to the new crown epidemic in the world, and the cumulative number of deaths due to the new crown in the United States alone has reached more than 920,000, while we only had thousands of deaths during the outbreak of the new crown in Wuhan in the early days, and after the end of the epidemic in Wuhan, there were almost no more cases of new crown deaths. These data are enough to prove that "dynamic zeroing" is not only effective for epidemic prevention and control and reduction of deaths, but also very effective for socio-economic development. Chinese people's current life should be said to be very happy, the people generally have a sense of security, although the outbreak of the local epidemic will have some impact on a small number of people, but from the perspective of the national chess game, the prevention and control of the epidemic, no country in the world can be as successful as China, it should be said that the "dynamic clearance" policy is the best way to prevent and control so far. If we don't find a new way to ensure that the virus doesn't spread widely after it is imported, and if there is no better way to control the outbreak, the strategy of dynamic zeroing will not be adjusted for the time being.
Source: Global Times