Views: 0 Author: Site Editor Publish Time: 2022-05-15 Origin: Site
Since the new crown epidemic, the virus has continued to evolve, from Alpha to Delta to Omicron, with new mutants appearing every few months on average. And various virus variants will split and evolve into different subtypes, such as Delta, which has more than 200 subtypes, as well as Omicron.
Recently, two new subtype virus variants of Omicron appeared in South Africa, bringing a fifth wave of epidemics locally.
1. South Africa ushered in a new round of outbreaks
According to media reports, as of the evening of May 7, local time in South Africa, the number of new confirmed cases of new crowns in South Africa within 24 hours was 8,524, and the positive detection rate of the virus was as high as 31.1%, which was a record high of 34.9% last year. On May 11, South Africa reported 10,017 new confirmed cases of the new crown within 24 hours, the first time this year that the number of confirmed cases in a single day exceeded 10,000.
At least 31 people out of every 100 people tested have been diagnosed, which means that the new crown virus is spreading rapidly in the community.
South African epidemiologists say that South Africa is currently experiencing a fifth wave of the epidemic. At the beginning of April, South Africa just announced the lifting of the national disaster state that had lasted for more than two years. As a result, the epidemic rebounded, and the situation was not optimistic.
South Africa, as one of the starting places of Omicron, has become the vane of the global new crown epidemic. In November last
year, the new mutant strain B1.1.529 of Omicron was first reported in ZBotswana, South Africa, and the BA.1 subtype strain became the mainstream virus at that time.
In February of this year, BA.2 replaced the dominance of BA.1. In a new round of outbreaks in South Africa, the new subtype strains BA.4 and BA.5 of Omicron became the dominant strains. So far, these two subtypes of the virus have been found in more than 20 countries and regions around the world, especially the United States.
Recently, new variants BA.4 and BA.5 have also begun to spread in the United States, but BA.2 is still the mainstream virus strain, and the next generation of BA.2, BA.2.12.1, is also spreading rapidly, and its spread is faster than BA.2 is 25% higher and has accounted for 52.3% of the new crown cases in New York, New Jersey and Connecticut. Facing the constant mutation of the new coronavirus, Fauci, the chief medical adviser of the United States, said in an interview that the traditional concept of herd immunity may no longer apply to the new coronavirus.
2. Continuous evolution, new strains have stronger escape ability
The BA.4 and BA.5 mutant strains that led to a new round of outbreaks in South Africa were derived from BA.2 and had stronger transmission ability than BA.2, BA.4 and BA.5. The leading cause of mass infection.
People are optimistic that as the new coronavirus continues to mutate, its harm will gradually decrease, and the mutation pattern will become more and more predictable, but we seem to ignore its "evolutionary" ability.
On May 6, the journal Nature published a new research article on BA.4 and BA.5 mutants.
Virus evolutionary biologist Jesse Bloom believes that the new BA.4 and BA.5 variants are more transmissible, partly because they are inherently better at transmission, and partly because the new mutants They are more prone to immune escape. They are better at evading the immune protection brought about by prior infection and vaccination. They can infect people with prior immunity, so they are prone to mass infection.
Bloom's team had previously found that both BA.4 and BA.5 carry a key mutation called F486V in their spike protein, which is responsible for infection and immune responses, that helps the mutants evade viral blockade Antibody.
The experimental results of the team of Academician Xie Xiaoliang of Peking University also found that the antibodies produced by BA.1 infection have a low protective effect on BA.4 and BA.5, and BA.4 and BA.5 have certain immune escape ability.
3. Why is the super mutant new coronavirus always born in South Africa?
From Beta to Omicron, as well as a variety of mutant branches, many were first discovered in South Africa and caused widespread infection, which makes people wonder why mutant viruses are always born in South Africa?
First of all, South Africa is the country with the most serious HIV epidemic in the world. The number of people infected with HIV is close to 8 million, ranking first in the world, and the HIV prevalence rate of adults is as high as 20%.
HIV, whose scientific name is human immunodeficiency virus, weakens the immunity of infected people, making them more susceptible to infection by other pathogens. Therefore, after HIV-infected people are infected with the new crown, the new crown virus can survive in the body for a longer time, and these patients will become "Petri dishes", increasing the probability of the new crown virus.
Secondly, with a total population of more than 60 million, South Africa is the 24th most populous country in the world and one of the countries most severely affected by the new crown epidemic. Due to the huge base of infection with the new crown, the probability of generating new mutant strains will also be much greater.
Furthermore, the vaccination rate of the new crown in South Africa is relatively low, the overall vaccination rate is less than 50%, and only 45% of adults are fully vaccinated, which makes most of the population susceptible to the new crown, and the virus is not easy to clear, which increases the probability of virus mutation.
Of course, the ability to discover new variants of the virus first shows that South Africa has a strong ability to monitor viruses. South Africa is one of the very few well-developed countries in Africa. It has a strong scientific and economic foundation, and its virus detection capability is even stronger than that of many developed countries.
All in all, we cannot underestimate the harm of the new crown virus prematurely. Active prevention, vaccination, and exercise to improve immunity are the best strategies.
