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The newest and most severely mutated strain of the new crown virus has spread in South Africa and aroused global attention. The British authorities designated it as a new mutant strain under investigation. Many governments quickly adopted anti-epidemic measures such as travel restrictions. Major stock markets in various regions heard news. Plummet.
Some experts say that the latest mutant strain is the “worst mutant strain” so far. One of the most worrisome sinister aspects is that it seems to be very different from the original new coronavirus, which means that it targets known viruses and mutant strains. The effects of vaccines and drugs developed may be affected.
But it is too early to make this judgment.
Why is this latest mutant strain worrying? What do we already know?
Where and when was it first discovered?
B.1.1.529 was first discovered in South Africa’s neighboring Botswana on November 11. Three days later, on the 14th, South Africa recorded the world’s first case of B.1.1.529 infection.
On November 25, the South African National Institute of Infectious Diseases announced the confirmation of this latest mutant strain, saying that this mutant strain has high infectivity and the risk of immune evasion that the vaccine is difficult to work on. Details are yet to be observed and analyzed.
So far, 77 cases have been confirmed in Gauteng Province, South Africa, 4 cases in Botswana, and 1 case in Hong Kong (a 36-year-old man traveling to South Africa). There are signs that this variant has spread more widely.
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Which variants are known about South Africa?
The degree of mutation of the latest variant of the new coronavirus is very serious. Professor Tulio de Oliveira, director of the South Africa Epidemic Response and Innovation Center, said that there is an “abnormal mutation group” and that it is “very different” from other variants currently in fashion, which is “surprising.”
The most worrying thing is that this virus is now completely different from the original virus that appeared in Wuhan, China. This may mean that a vaccine designed based on the original strain may be less effective.
But this issue needs further follow-up research and more data.
Professor De Oliveira said at a briefing that there are a total of 50 mutations, and there are more than 30 mutations in the spike protein; the spike protein is the key to the virus invading the human cell, and it is also the target of most vaccines.
Ten mutations were found in the receptor binding domain, the part where the virus first comes into contact with human cells. As a control, the Delta mutant strain currently sweeping the world has only 2 mutations.
Such a severe mutation is likely to occur in an infected person who is unable to resist the virus.
Professor James Naismith, director of the Rosalind Franklin Institute at the University of Oxford, told BBC Radio 4’s Today program that this variant strain “almost certainly” will reduce the effectiveness of the vaccine, but the vaccine is still effective to some extent, and the treatment of Covid- 19’s new drugs may not be affected.
He said that this variant has not been proven to be more transmissible, but it has mutations consistent with the Delta variant and seems to spread faster than other variants.
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The global spread of the new coronavirus continues to mutate
Which ones don’t know yet?
The biggest question about the latest variant: Which vaccines is it resistant to? To what extent does it evade the immune system? Is the toxicity more serious? Does it spread faster than Delta?
BBC Health and Technology News reporter James Gallagher said these questions cannot be answered at this time.
According to existing virological analysis data, 90% of the new crown infection cases in Gauteng, South Africa may already be this variant strain, and it “may already exist in most provinces in South Africa.”
However, Gallagher analyzed that this does not tell us whether it spreads faster and more severely than the Delta variant, or to what extent it can evade the immune protection brought by vaccination.
In addition, the complete vaccination rate in South Africa is 24%, and there is currently no data showing the spread of the latest variant in other countries/regions with a higher vaccination rate than South Africa.
Professor Neil Ferguson of Imperial College London said that travel restrictions are “cautious”, but it is not clear whether this variant is more contagious or resistant to vaccines, so it is now judged for its potential risks. premature.
What are the main variants?
According to the WHO definition, a “notable” strain has the following characteristics: it appears in multiple countries/regions, and the mutation has a confirmed or suspected significant impact on the infectivity and severity of the virus.
Variant strains that are “of concern”-those with increased infectivity, harmful changes in epidemiological sense, increased toxicity, changes in disease symptoms or manifestations, and evidence of testing, treatment, and preventive measures (such as vaccination) Effectiveness decreases.
In addition to the newly discovered mutant strains in South Africa, four known mutant strains are currently the most interesting:
- Delta mutant strain (B.1.617.2), first discovered in India,
- Alpha mutant strain (B.1.1.7), first discovered in Kent, England, has spread to more than 50 countries/regions, and may still be mutating.
- Beta mutant strain (B.1.351), first discovered in South Africa, has spread to at least 20 other countries/regions
- Gamma mutant strain (P.1), first discovered in Brazil, has spread to more than 10 other countries/regions
Alpha, Gamma, and Beta mutant strains all have a mutation called N501Y, and this mutation seems to strengthen the virus’s ability to infect cells and make it easier to spread.
The Beta and Gamma mutant strains also have a key mutation called E484K, which may allow the virus to evade the immune system. Delta mutant strains may spread more easily.
They are included in the World Health Organization (WHO) on the list of “concerned” variants that need attention because they pose a greater threat to public health, such as more infectious viruses, which can lead to more serious illnesses or greater resistance to vaccines. powerful.
Other important mutant strains are listed as “worthy of attention” because they have been found to spread in multiple countries or cause disease clusters.
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How does the virus mutate?
Every time a new coronavirus infects the human body, it is the result of the SARS-CoV-2 virus constantly replicating itself. Every time it replicates, it copies its own genome. Small errors may occur during the replication process. Therefore, the new genome may be different from the previous one. Is slightly different.
Simply put, these small mistakes are mutations, also known as mutations, resulting in mutated strains of the virus; mutations will continue to occur, and there will be more and more mutated strains.
Most mutations have no effect on the behavior of the virus, but occasionally, mutations can also cause changes in the behavior of the virus.
There are two main mutations discovered so far, both of which appear on the spike protein of the new coronavirus; the spike protein is an important part of the virus to unlock the entry into human cells.
The N501 mutant strain changes the most important “binding receptor” of the new coronavirus spike. This is where the virus spike first contacts human cells. Any mutation that makes it easier for the virus to enter the cell will give it more advantage.
Another mutation is the deletion of H69/V70. Research by Professor Ravi Gupta of the University of Cambridge showed that this mutation doubled the infectivity in laboratory experiments and at the same time reduced the effectiveness of antibodies in the survivors’ blood attacking the virus.
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Since the beginning of the new crown epidemic, the virus has undergone thousands of large and small mutations
What is the difference in the behavior of the mutant strain?
The virus has a variety of techniques in the process of adapting to make it easier to spread. E.g:
- Invade human cells more effectively;
- Dive deeper into the early warning mechanism of human cells;
- Survive longer in the air;
- Increase the amount of virus released by patients’ breathing and coughing;
Viral mutations involve advances and retreats in an evolutionary sense-progress on the one hand may come at the cost of retreat on the other. For example, the virus may sacrifice part of its transmission ability in the process of contending with the vaccine.
The extent to which the virus will mutate is currently difficult to predict, because it is not only the number of mutated strains, but also various factors such as infectivity, harmfulness, and effective time of immunity.
The most effective way to curb the endless emergence of mutated strains of the new coronavirus is to reduce the number of global new coronavirus infections, because each new infection is an opportunity for the virus to mutate and change behavior.
Why is it important to track mutant strains?
The production of mutant strains is the result of mutations in the process of virus self-replication. The virus will continue to replicate itself during its lifetime, and during this period it will often mutate and produce mutated strains. The more replicated, the greater the number of people infected, the greater the probability of mutation and the number of mutations.
Variant strains that need to be vigilant can cause the virus to reproduce more easily, spread faster, or become more resistant to vaccines and drugs.
Many mutations are not necessarily a bad thing, but mainly depend on what effect these mutations actually play.
Tracking and understanding the characteristics of mutant strains and the scientific rationale behind them are crucial to the development of vaccines and drugs.