Share with wechat scanning QR code < / P > < p > to friends and circle of friends < / P > < p > [compiler / observer Network & nbsp; Li Huanyu, a briefing released in August 3rd by the American Academy of infectious diseases (ISDA) showed that the spread of COVID-19's variant Delta has increased the proportion of the population needed to achieve the group immunity to 80% or even 90%, far higher than the 60% lowest threshold previously announced by the World Health Organization. p> < p > delta variant leads to a significant increase in the population immune threshold < / P > < p > according to Bloomberg on August 3, Richard Franco, an assistant professor at the University of Alabama at Birmingham, said at the briefing meeting that the delta variant strain is "a very dangerous virus, much more dangerous than the original strain." Because its infectivity is twice that of the original species, the proportion of population required to achieve mass immunization is much higher than the previously estimated 60% - 70%, reaching 80%, or even close to 90% < p > Richard Franco & nbsp; Video screenshot < / P > < p > the so-called "mass immunization" refers to that when a certain proportion of the population obtains immunity through vaccination or previously infected with the virus, it can reduce the spread of the virus, so as to protect a wider range of people < p > for the population proportion required to achieve mass immunization, the figure given by who in November last year was 60% - 70%; American infectious disease expert fudge changed his mouth several times. Last December, he raised the threshold from 60% - 70% to 70% - 90%; In July 31st, academician Zhong Nanshan delivered a speech in Guangzhou on the status quo and judgement of COVID-19, saying that the latest research results still have protective effect on China's vaccine to the delta strain, and that 83.3% of the people need to have a vaccine before it is possible to establish a group immunity. p> < p > American experts also agree with the protective effect of vaccine on Delta variant. Fox News quoted Franco as saying on August 4 that although delta is more dangerous than the previous strain, most confirmed, hospitalized and dead cases are unvaccinated people, which means that the vaccine is still playing a role < p > Franco said: "the data show that vaccinated people are eight times less likely to be infected with delta variant and 25 times less likely to be hospitalized than unvaccinated people. If hospitalized, novel coronavirus pneumonia is less likely to die of new pneumonia than 25 times the number of people who did not receive the vaccine. The more people are vaccinated, the stronger the protection of "mass immunization" for those who are not vaccinated < p > he also added that the average age of patients in his hospital and other places is becoming younger than the peak of the epidemic. Some pediatric hospitals also reported that the number of children who do not meet the vaccination conditions is on the rise. In this regard, Ezekiel Emanuel of the Institute of health transformation at the University of Pennsylvania believes that this may be due to the high vaccination rate of the elderly, especially the elderly over the age of 65. When a large number of people are infected, even if the hospitalization rate and mortality rate are very low, the number will rise < p > according to the U.S. Centers for Disease Control and prevention, nearly 60% of Americans have received at least one dose of new crown vaccine, and about 50% have been fully vaccinated, which may reach 165 million. Meanwhile, during the epidemic period, about 35 million people in the United States tested positive for COVID-19. p> < p > American infectious disease expert fudge once said that the reason why he mentioned the low number at the beginning was that many Americans were still wary of vaccines at that time. With opinion polls showing that Americans are less skeptical about the vaccine, he believes that it is time to release the "hard news" < p > the viral load of delta variant cases is 1260 times that of the original strain cases < / P > < p > since it was first found in India at the end of 2020, delta strain has swept the world and has become the main strain in many regions. The world famous authoritative journal Nature published two articles on July 21 and 28 to introduce the risk of this strain < p > the article on the 21st published the research of Guangzhou CDC on the first batch of delta variant cases in China. The researchers said that people carrying the delta variant would detect the virus four days after exposure to the virus, while those carrying the original strain would take six days, indicating that the replication speed of the delta variant is much faster. The difference between the two in virus load (an index to measure the density of virus particles in the body) is closely related to this. Research shows that the virus load of delta variant cases is 1260 times higher than that of the original strain cases, so it is easier to spread

COVID-19 and cell fusion animation   Picture source: nature < / P > < p > the article in nature on the 28th pointed out that there were more mutations in the S protein of delta variant compared with other variants, which improved the binding ability of S protein to receptors on cell membrane and strengthened the ability of virus to escape the immune system. However, the article also said that the current scientific community's understanding of COVID-19 is still superficial, and it is not easy to keep pace with the virus mutation. p> < p > this month, a new study reported that delta mutant proliferates faster and has higher content in human lungs and throat. There is no final conclusion about this phenomenon, which is also the direction of many experiments

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: Chinese medicine: mAb is effective for new crown variants such as delta. According to the 4 WeChat China's official account of "China Life", recently, the team of Chinese biological Yang Xiaoming researchers recently found that the monoclonal antibodies against the delta mutants were effective, and the neutralization activity of IC50 was as high as 5ng/ml. < p>

p> < p > using phage display technology, the immune library was established with peripheral blood mononuclear cells (PBMC) of 8 convalescent patients with sars-cov-2 infection as gene raw materials, and several monoclonal antibodies with high and activity against sars-cov-2 were successfully screened. The data of crystal structure analysis showed that the RBD epitope recognized by the most active antibody 2B11 was highly overlapped with the binding site of ACE2, which effectively blocked the binding of COVID-19 to ACE-2 on the cell surface and prevented the infection of cells. p> < p > at the same time, the research team also used the IFNAR - / - mouse model transduced by hace2 adenovirus (hace2 ADV) to evaluate the preventive and therapeutic effects of 2B11 on sars-cov-2 infection. The results showed that compared with the control group, 2B11 administration before or after challenge could significantly reduce the weight loss and pulmonary viral load caused by virus infection; Further analysis of lung pathological sections showed that the application of 2B11 could significantly reduce the lung inflammation caused by virus infection

B.1.617.2 has novel coronavirus pneumonia spread worldwide, and is also the current domestic mainstream. ?
2023-03-22 10:04:39