Since March 2022, a new round of new crown pneumonia epidemic caused by the mutant strain of Omicron has spread to most provinces in China, and various places have raised the level of epidemic prevention to deal with it. The new crown pneumonia pandemic (pandemic) in the sense of public health has been raging for more than two years, and China is the only major country that has not “flattened” in the field of epidemic prevention. The results of the fight against the epidemic are inseparable from the strong leadership of the party and the government and the strong cooperation of the people, which fully reflects the superiority of the Chinese system.
Objectively speaking, the prevention and control of the epidemic has indeed brought some inconvenience to personal life-schools organize online classes, companies arrange home office, and it is difficult to go out. If not, they were forced to isolate. The free state of life before 2019 is “like a lifetime” when I think about it now. As a result, some young netizens sighed: “Youth is only a few years old, and the epidemic is three years old!”
I am afraid that only after the end of the new crown pneumonia pandemic can everyone’s life return to the state of freedom before 2019. At present, the epidemic is still in the anxious stage. The question that everyone is generally concerned about is when will the new crown pneumonia pandemic end?
At present, it is necessary to give a scientific and reasonable explanation for this problem. Because, if the understanding of this issue is not clear enough, it is likely to lead to the public’s misjudgment of the epidemic, resulting in serious consequences due to paralysis and laxity. Science pays attention to objective laws, and objective laws do not change with people’s subjective will-no matter whether you are happy or not, the law of conservation of mass and energy will not change. As a scientist, I will first draw conclusions on the above issues from a scientific point of view:
It is impossible to predict when the new crown pneumonia pandemic will end, but with a high probability, it will not end in the next 2 years.
Put the conclusion here first, and then let’s talk about the specific reasons. Why is it impossible to predict when the COVID-19 pandemic will end? Because the new coronavirus is rapidly mutating, the immunity obtained from previous infection with the new coronavirus or vaccination is not enough to completely resist the mutated virus. This important biological mechanism is called “immune escape”. Next, we have to explain the mechanism of immune escape, and then explain why the new coronavirus is difficult to deal with.
The basis of immune escape lies in the spontaneous mutation of the viral genome. The new coronavirus SARS-Cov-2 is a virus with RNA as the genetic material, and the replication of genetic information follows the principle of “from RNA to RNA”. However, the RNA-dependent RNA polymerase that completes this process, like a careless schoolboy, will always inadvertently make typos when copying; then, the article with the typo is passed on to other careless schoolboys, who will again misspelled other words. In the end, the mistakes are added, and the article on the virus genome is completely unrecognizable. Since the outbreak of the new crown virus at the end of 2019, a large number of mutants of the new crown virus have appeared, from Alpha, Beta, Delta, and now Omicron. On this trend, until next year, it’s hard to say whether the Greek alphabet will be enough.
The key to immune escape is the failure of neutralizing antibodies. The so-called neutralizing antibody refers to the antibody that can prevent the virus from invading the target cell. Taking the new coronavirus as an example, the S protein on the viral capsid binds to the ACE2 receptor on the cell surface, allowing the virus to enter the cell by endocytosis. Human vascular endothelial cells express more ACE2 receptors and thus become the target cells of the new coronavirus. Strictly speaking, the new coronavirus does not cause simple “pneumonia”, but a systemic vascular endothelial cell disease, but the damage to the lungs is the most obvious.
In the more than two years since the new coronary pneumonia pandemic, the research on the sequelae of new coronary pneumonia has just started, but the confirmed sequelae include dizziness, headache, nausea and distraction and other central nervous system symptoms, and even damage to the heart, kidneys and other organs. The neutralizing antibody induced by the vaccine can bind to the S protein, thereby preventing it from binding to the ACE2 receptor on the cell surface, making the new coronavirus unable to enter the target cell, which provides a protective effect.
After infection with the new coronavirus or vaccination, neutralizing antibodies against the S protein will be produced in the human body. The binding of neutralizing antibodies to antigens relies on 4 forces, hydrogen bonding, electrostatic force, van der Waals force and hydrophobic interaction. These four forces are jointly formed by the amino acids of the antibody complementarity determining region and the antigenic epitope. If the spontaneous mutation of the viral genome leads to changes in the amino acid sequence constituting the antigenic epitope on the S protein, the force field between the antigenic epitope and the antibody complementarity-determining region will change. The antibody complementarity determining region cannot bind to the antigenic epitope with high affinity, and the neutralizing antibody is ineffective if a slap fails. Taking the Omicron mutant as an example, there are as many as 32 mutations in the S protein. It is precisely because of the existence of a large number of mutations that the titer of the neutralizing antibodies produced by the vaccine against the Omicron mutant is greatly reduced. According to a report by the French research team in December 2021, even if the neutralizing antibody produced by the booster shot of the Pfizer vaccine has some effect on Omicron, the titer is 6-23 times lower than that of the delta mutant. The trouble with immune escape is obvious.
Image source: https://doi.org/10.3389/fimmu.2021.830527
Since vaccination against the new coronavirus is not enough to completely protect against mutated virus infection, why should it be actively vaccinated? Don’t underestimate the country’s decision-making power in the field of public health. Vaccination is well scientifically based – “not enough to fully protect against” does not mean “totally inadequate protection”.
To be more specific, vaccination against COVID-19 does not guarantee immunity from mutated virus infection, nor does it guarantee that the infected person is not contagious, but it can greatly reduce the probability of the infected person becoming seriously ill. The specific mechanism here can be explained with the help of a slide from Moderna, the manufacturer of the new crown vaccine:
As shown in the figure above, after vaccination, the immune protection produced in the human body comes from neutralizing antibodies, antigen-specific CD4+ memory T cells, antigen-specific CD8+ memory T cells, antigen-specific memory B cells, and possibly non-neutralizing antibody. These several substances that provide immune protection can constitute “defense in depth”. If the protective effect of neutralizing antibodies is insufficient, the new coronavirus will still infect some target cells; but at this time, antigen-specific CD4+ memory T cells will provide an additional layer of protection. After they recognize the conservative antigenic epitopes of the new coronavirus, they will induce immunity The system produces more types of neutralizing antibodies; antigen-specific CD8+ memory T cells and memory B cells will not be idle, respectively performing the functions of killing infected cells and secreting antibodies.
Whether it is domestic inactivated vaccine, recombinant protein vaccine, or foreign mRNA vaccine, it can greatly reduce the probability of severe new coronary pneumonia. From the perspective of domestic epidemic prevention practice, since the Wuhan epidemic was eliminated in early 2020, the situation of “ICU overcrowded” has never occurred again, largely due to the popularization of vaccination.
Therefore, even if the new coronary pneumonia vaccine is not perfect, it is still necessary to actively vaccinate, and it must be 3 shots. A recent study published by Professor Jin Tengchuan of the University of Science and Technology of China confirmed that three doses of the new coronavirus vaccine are sufficient to produce lasting immune protection, but the additional benefit of the fourth dose is not obvious. Out of respect for science and love for relatives and friends, please vaccinate consciously.
After talking about immune escape, we have to analyze it carefully. Why is the new crown pneumonia pandemic endless and new mutant strains emerging one after another? Even the newer Omicron mutants have further differentiated into a more powerful BA.2 version.
Chinese researchers have really calculated the mutation probability of the new coronavirus, or the probability of a primary school student copying a typo. Based on the virus sequencing data of a large sample in the United States, the mutation rate of the entire genome of the new coronavirus is 6.677×10-4/locus. Year , the mutation rate of the gene encoding S protein was 8.066×10-4/site.year. The above mutation rate is considered to be in the middle of the group of RNA viruses, but why does the new coronavirus have a dazzling number of mutant strains? This has to be explained by probability theory: as long as the sample is large enough, even the smallest event will happen.
From a microscopic level, the mutation probability of the new coronavirus genome at each replication is certain; however, the probability of the new coronavirus genome mutating in a macro-infected population is the sum of the microscopic individual probabilities. That is to say, the larger the base of the infected population, the greater the probability of the emergence of new mutant strains of the virus. As most countries in the world are completely “flattened” in terms of epidemic prevention, the out-of-control epidemic has created a huge number of infected groups. According to statistics from Johns Hopkins University in the United States, as of March 27, 2022, a total of 480 million people worldwide have been infected with new coronary pneumonia. Although the mutation rate of the new coronary pneumonia genome is considered to be at the middle level among RNA viruses, multiplied by such a large base of infected populations, mutant strains will inevitably pop up every three forks and five. What’s more, the more infectious mutant strains can quickly overwhelm earlier strains in transmission. Judging from the data in the United States, it took only a month or so for the Omicron mutant to replace Delta and earlier strains.
As mentioned above, with a high probability, the new crown pneumonia pandemic will not end in the next two years. The starting point for making the above judgment is actually the status quo that foreign countries are completely “flattened” in terms of epidemic prevention measures. According to a rough estimate, that is, the total number of confirmed cases – the number of recoveries – the number of deaths, there are nearly 60 million existing cases of new coronary pneumonia. To put it uglier, those countries that have adopted a “flattening” attitude towards epidemic prevention have created huge “virus reservoirs” and are now “cultivating the whole people”.
To make matters worse, the group carrying the new coronavirus is no longer just humans – the new coronavirus can spread across species, a considerable number of white-tailed deer infected with the new coronavirus have been found in the eastern United States, and studies have shown that white-tailed deer have emerged within the group. chain of infection. According to estimates by the U.S. Department of Agriculture, there are as many as 30 million white-tailed deer in the United States, which may constitute another huge “reservoir of viruses”. As for animal groups that are more susceptible to the new coronavirus, such as bats and monkeys, it is difficult to say what the current situation is. In a scientific sense, it is entirely possible for the new coronavirus to generate an independent chain of infection within the animal population, evolve new mutant strains, and finally reintroduce the mutant strains to the human population.
To put it bluntly, what the next mutant of the new coronavirus will look like, and whether it will have stronger infectivity and virulence, does not depend on China, where the whole nation is fighting the epidemic, but precisely on those countries that “lie down”. It is because of the irresponsible attitude of the governments of these countries to their own people that the mutant strains are constantly being renovated and spilled everywhere. Since we cannot control the behavior of other governments, and it is difficult to quickly resolve the huge “reservoirs of viruses” (including humans and animals) in other countries, we cannot predict when the COVID-19 pandemic will end. This is not a pleasant conclusion, but it is the most reasonable and credible reasoning from science.
However, U.S. experts have previously predicted that the global new crown pandemic is likely to end in March 2022. To put it bluntly, this kind of argument just caters to the unrealistic and wishful thinking of some people and has no scientific basis. Just ask these blindly optimistic people, can you stop the replication of the new coronavirus in the “virus reservoir” of other countries? Since it can’t be done, how can you guarantee that new mutants of the new coronavirus will not appear?
This kind of blindly optimistic argument is essentially advocating “the theory of quick victory in the fight against the epidemic” – as long as you survive these few days, you will be fine. However, due to the continuous import of overseas epidemics, the domestic anti-epidemic cannot be won quickly, and will inevitably fall into a protracted war. In this historical context, the “quick victory in the fight against the epidemic” will breed luck, lead to slack top-down thinking, and ultimately cause huge losses.
To this day, some people with ulterior motives can still be seen advocating absurd remarks such as “coexisting with the virus”, “in line with international standards”, and “can’t hold on hard, need a soft landing” on the Internet. It’s really worth breaking it down and talking about it.
l Just ask those “people” who advocate “coexistence with the virus” – let yourself be infected with the virus first, and then infect your parents, will you do it? The starting point of the “coexistence theory” is actually extreme individualism, the fantasy of sacrificing others in exchange for one’s illusory “freedom”.
l “In line with international standards”, it is even more ridiculous – what are the things worth learning from the anti-epidemic measures of Western countries? Is it possible to learn that they “lay flat” directly to be considered “connected”? The starting point of the “connection wheel” is actually the centralism of Western civilization and the mentality of being colonized by spirituality. I subconsciously feel that what Western countries do is right, and China cannot do better than them.
l What is a “soft landing”? Only when the epidemic is under control without causing economic stagnation and inflation can it be called a “soft landing”. From this definition, China has been working on a “soft landing” for more than two years, while Western countries have never “landed” at all. It is precisely because China has actively fought the epidemic and ensured the normal operation of the economic fundamentals that the “soft landing” has been achieved. It can be said that without the whole country actively fighting the epidemic, there will be no “soft landing” and 5.5% GDP growth target.
l As for “can’t stand it hard”, it is also a manifestation of lack of self-confidence – none of the Western countries that pursued “lying flat” and stopped epidemic prevention have returned to normal operation. If the worldwide epidemic continues for a few more years, it is a big deal that Western countries will collapse from within due to the rupture of the economic chain, and China is still expected to achieve the rise of a great power by relying on internal circulation. Our generation may become witnesses to history. On the one hand, we have witnessed that the new crown virus has become a pathogen that has profoundly changed the course of human history since modern times.
During part of 2020 and 2021, I witnessed how the epidemic prevention measures collapsed in the United States: from short-term lockdowns and separate policies, to full liberalization and complete “laying flat”, it only took half a year, and then it was a piece of chicken feathers. . In capitalist countries, no one is willing to take actual responsibility, everything depends on “God bless”, and the result is that the virus is allowed to rage and the people are left to fend for themselves. Therefore, the epidemic prevention system is actually irreversible. Once the dam is washed away by the flood, it will be difficult to return to the state of strict defense.
