The Indian government predicted on April 25 that the country’s new crown epidemic may reach its peak in mid-May. Following Maharashtra, Gujarat and the capital New Delhi, Uttar Pradesh will become the next hot spot for the epidemic. By the end of this month, Uttar Pradesh, Maharashtra and New Delhi will be the regions with the fastest new cases. When the epidemic reaches its peak in mid-May, India will have up to 500,000 new confirmed cases every day.
The Indian government is overly optimistic about the epidemic, and the outcome is completely uncontrollable. 1. The latest data is just the tip of the iceberg, 314,800/day is not even a fraction of the actual number of infections. 1. The positive rate of detection is too high, indicating a serious missed detection. From the perspective of detection capability, the daily detection capability does not exceed 1 million. From this data, we can see that in the 20 days from March 25 to April 15, India detected 15.437 million people, an average of 770,000 people per day. (1) According to the test data of 770,000, the positive rate is about 42.18%. (2) Fifty-three out of 188 people on the flight from India to Hong Kong were diagnosed with a diagnosis rate of 28.2%. 2. The high test positive rate indicates that the missed test is serious. According to our country’s routine, if a positive patient is detected, his close contacts and general contacts must be tested. Due to the low infection rate among close contacts, the positive rate after detection of general contacts is unlikely to be higher than 3%. The situation in India can only be said that even patients cannot be found, and the test results can only be seen as the results of a sample survey. 3. The population serum antibody data shows that the high infection rate has been maintained for a long time. New Delhi authorities have completed five antibody surveys. In the first survey conducted between June 27 and July 10, 2020, the COVID-19 antibody carrying rate in the samples was 22.9%, and the sample size was 21,387. August 2020 When the second survey was conducted in New Delhi, the positive rate of antibodies in the population of New Delhi was 29.1%, males 28.3%, females 32,2%, and the sample size was 15,000. The infection rate under 18 was 34.7%, the infection rate between 18 and 50 was 28.5%, and the infection rate was over 50. The infection rate was 31.2%.   In the third survey in September 2020, the positive rate was about 33%. The fourth survey from October 15 to 21, 2020 involved 15,015 people, of which the infection rate was 26.1% for females and 25.06% for males.  In January 2021, the fifth survey of 60% of people in New Delhi was positive for antibodies, with a sample size of 28,000 and an infection rate of 60%.  [Global Times reporter Ni Hao] In the fifth round of serum antibody testing against the new coronavirus in India, 60% of the 28,000 samples from New Delhi were tested positive for seroantibodies. According to Indian media reports, there are about 20 million people in New Delhi, which means that at least 10 million people have been infected with the virus. This data is regarded by the Indian media as a great benefit in fighting the epidemic, and it is believed that New Delhi will achieve herd immunity just around the corner, or is moving towards herd immunity. The sixth investigation is currently underway, and the results have not been released. Comparing the data from Wuhan, my country: The National New Coronary Pneumonia Seroepidemiological Survey organized by the Chinese Center for Disease Control and Prevention recently (end of 2020) shows that the positive rate of new coronary antibodies in the community population in Wuhan is 4.43%, and the positive rate of antibodies in other cities and prefectures of Wuhan, Hubei is 0.44%. Among more than 12,000 people in six provinces outside Hubei, only 2 cases of antibody positive were detected, and the positive rate was extremely low. 5. So a conclusion can be drawn: By January 2021, more than half of the people in New Delhi have basically been infected again. According to the traditional view, January has reached the level where most people have antibodies, not far from “herd immunity”, and the epidemic should gradually slow down. From the first picture, the detection capability has not changed much in the past six months, so the recent surge in cases reflects the increase in the population infection rate, which is inconsistent with the situation that “the majority of people will improve if they have an antibody epidemic.” 2. Possible reasons for the surge in cases: The virus continues to evolve to adapt to the environment with antibodies and vaccines. The new coronavirus is a positive-strand RNA virus with a high probability of natural mutation, reaching between 0.0001 and 0.000001. The larger the virus population (the more infected people) and the longer the duration of a single infection, the greater the probability of virus mutation. 1. The larger the virus population and the longer the infection time, the greater the probability of mutation (1) A large population will increase the probability of mutation. Assuming that the probability of a viable mutation of the virus in a certain patient, for a host population of n, the probability of a viable mutation of the virus is. Even if it is very low, as long as n is large enough, it will be close to 1. (2) The long infection time is conducive to the discovery of the new coronavirus with 18 mutation points in the body of the mutant Russian woman. Konstantin Krutovsky, a professor at the Department of Genomics and Bioinformatics at Siberian Federal University, pointed out that this research work has confirmed for the first time the fact that “the long-term existence of a new coronavirus in an organism will cause a large number of mutations. “.  A paper published in the New England Journal of Medicine (NEJM) on December 3 described an immunocompromised patient in Boston who was infected with the new coronavirus 154 days before his death. The researchers found several mutations in the strains extracted from his body, including the aforementioned N501Y. Researchers believe that the new crown variant strain B.1.1.7 may also originate from long-term patients with low immunity, and has gone through a long evolutionary process, and only spread the strain to the outside world in the later stages of infection. The gene sequence shows that this new coronavirus mutant strain has accumulated many mutations, which together lead to changes in the virus protein at 17 sites, of which 8 occur in the important spike protein (S protein). 2. Quantitative analysis The above analysis can get that the overall mutation probability of the virus is related to the virus population number (infected number * per capita virulent amount) and infection time, and P (virus mutation probability) can be obtained (number of patients * average duration of infection of patients) *The average number of patients carrying the virus),) In addition, if a patient is cured in a completely isolated environment (completely eliminated the virus), the mutant virus in his body will be “suffocated”. P (probability of mutation prevalence) = P (probability of viral mutation) the probability that a patient cannot infect the next healthy person)) so P (probability of mutation prevalence) ((number of patients * average duration of infection of patients * average number of patients with virus), ) The probability that the patient will not be able to infect the next healthy person)) 3. India has become a petri dish of the mutated virus. Because of the passive prevention of epidemics, most patients have been infected for a long time and most infected people move freely, so the mutation is very serious. India first discovered 240 mutated viruses at the end of February 2021. Later, in the samples collected from 18 states in India, 771 new coronavirus mutations were found in 771 samples. Among them, 736 were positive for the British variant, 34 were positive for the South African variant, and 1 was positive for the Brazilian variant, covering the global category. Subsequently, the researchers found as many as 7684 virus variant genomes in more than 5,000 samples, which means that some patients were infected with more than one variant virus.  4. Antibodies and vaccines are the selection pressure of virus evolution. Selection pressure is a concept in evolutionary ecology. It refers to the pressure exerted by the external environment on the evolution direction of the species. Different external pressures cause the species to evolve in different directions. If: the selection pressure of a gene is 0.001, then a dominant gene with a frequency of 0.00001 can be increased to a frequency of 0.99 with only 23,400 generations. In nature, when the selection is high, new varieties can be formed in a short period of time. For example, when penicillin was invented, bacteria generally did not have drug resistance. In an environment where antibiotics were commonly used, a small number of resistant bacteria were screened out and became the mainstream. The population change under high selection pressure is “natural selection, survival of the fittest”. If a virus has the characteristics of being able to adapt to the environment, its spread will increase significantly, thus occupying a major proportion. Third, the evolution direction of the virus 1. Stronger heat resistance. According to the general law of respiratory infectious diseases, viruses rely on droplets to spread, and droplets cannot exist for a long time in hot weather. Therefore, under normal circumstances, respiratory diseases are only high in the cold season. The recent outbreak in India shows that the virus has fully adapted to the high temperature environment in India. 2. It is more transmissible. 3. It can continue to spread among people with antibodies. The Ministry of Health of India pointed out in a statement that the new mutant new coronavirus discovered in the state of Maharashtra in the country has double mutations, and the strain samples Two mutations, E484Q and L452R, appeared at the same time, which may weaken the immune effect and become more infectious. This double mutant virus has been named “B.1.617” and is currently spreading rapidly in India. The E484Q mutation is similar to the E484K mutation carried by the mutant strains found in South Africa and Brazil. The E484K mutation is also called “escape mutation” because it can change the shape of the viral spike protein and protect the virus from vaccines or antibodies caused by early new coronavirus infections. The L452R mutation that was discovered in Denmark and California is also believed to be able to escape cellular immunity. According to Sujeet Singh, an official in charge of the Indian disease control project, in Delhi, a region with a population of more than 20 million, half of the confirmed cases were infected with the mutant strain, and many of them were young infected. 5. May resist existing vaccines. After universal vaccination, viruses that do not have vaccine-resistant properties will soon be eliminated. If patients who happen to have vaccine-resistant mutant strains are not in an isolated environment, such mutant viruses are likely to spread and become mainstream strains. 5. The direction of the lethal mutation is uncertain. Because the new crown has a long incubation period and can be transmitted during the incubation period, the disease is long and slow to death, even if the fatality rate is high, it will not have a significant impact on the transmissibility. Therefore, the prevalent virus must be a more transmissible species, but not necessarily a less lethal species. 6. If you are repeatedly infected with multiple strains, it may also trigger the antibody-dependent enhancement effect (ADE effect). After a person is infected with the new crown again, the antibody originally produced by the body may not work against the mutated virus. And at this time, because the human immune system mistakenly believes that the virus has been “suppressed”, the human immune system is completely defenseless against the virus at this time. This will cause this patient to have more severe symptoms after being infected with the mutated virus than those without antibodies. 4. Impact on the international epidemic prevention situation. Due to the poor public health level in India, the large number of infected people, and the serious cross-infection of different strains, it is almost inevitable to develop strains that are more transmissible and more resistant to antibodies and vaccines. Strains will develop under selective pressure. Since many countries have not quarantined and rigorously tested all incoming Indians, the mutant strain is expected to have spread to other countries. Only countries with strict prevention and control such as China can maintain relative security, but the risk of imported epidemics will also increase, and prevention cannot be relaxed. 5. Summarizing the history of human development is almost the history of fighting the virus. There are only a limited number of infectious diseases that can be eliminated by humans, such as smallpox. Therefore, the virus should not be underestimated and the virus will remain unchanged. After the vaccine is in place The epidemic can be completely ended. When considering epidemic prevention measures, the evolutionary factors of the virus should be taken into account: 1. Do your best to achieve “collection due to collection”, only to isolate and treat all infected persons to eliminate the possibility of the spread of the mutant virus. 2. Vaccines should be popular, but the effectiveness of vaccines should not be overestimated, thinking that there are vaccines and everything will be fine.
Influenza, like the new crown, is also prone to mutations. Influenza vaccines continue to be developed, but the influenza viruses that circulate every year may be different, resulting in a decline in immune effectiveness.
- When using vaccines, we should cooperate with isolation and epidemiological investigation measures. Although we cannot prevent the production of mutant strains that weaken the effectiveness of the vaccine, we can prevent the spread of possible vaccine-resistant strains.