The daily increase of more than 100,000 cases in the United States, the epidemic is heating up again: from BA.4/5 to new strains, the epidemic is far from gone

Guided reading

Bill Gates, who previously claimed that Omikoron was the "big flu" , has been infected with the new crown in the past two days, and his symptoms are currently mi.

At the beginning of 2022, the mutants .

According to the WHO, in addition to South Africa, nearly 20 countries have detected the Omicron subtype strains .

The .

01

Mutation is an eternal topic: the emergence of .

On April 1, 2022, South African bioinformatician Eduan Wilkinson detected several abnormal viral gene sequences, which were later identified and named .

On April 7, a report from the UK Institute for Health Security showed that two new strains, .

On April 14, the World Health Organization said it began to closely monitor the spread of the .

So, what makes .

This starts with the mutation sites of .

According to the relevant information, we analyze these three mutation points one by one:

The first L452 mutation, the most critical mutation in the delta mutant strain, gave delta direct the advantage of spreading rapid.

The second mutation, F486V, is located on the virus's spike protein, close to the site where the spike protein binds to the cellular ACE2 recept.

This mutation means that the site where the new coronavirus can be bound by antibodies has been mutated, and F486V may cause further immune escape of the virus, so this mutation greatly reduces the efficacy of the antibodies produced by the vacci.

The third Q493R mutation is a reversion mutation, which simply means that the mutant is completely or partially restored to the original genotype and phenotype after the second mutati.

02

Will there be a new wave? Transmissibility and escape of .

When it comes to new strains, our biggest concern is how scary it is, how fast it spreads, and whether vaccines are still usef.

Let's go through them one by one, let's talk about the speed of transmission of these two variants fir.

.

4 appears in mid-December 2021, while .

5 appears in early January 202 Researchers in South Africa found that the prevalence of these two variants has been on an upward trend since then, and by the end of April accounted for 60-75% of South Africa's new crown cases, becoming the mainstream strain in South Africa, and its transmission trajectory is as follo.

The spread of .

4 and .

5 in South Africa

According to "Nature", Penny Moore, a virologist at the University of the Witwatersrand in Johannesburg, South Africa, said that South Africa is entering a new wave of new crowns, and the "murderers" of this wave are undoubtedly .

4 and .

The researchers estimate that the growth in the number of .

4 and .

5 cases in South Africa is not optimistic, with an average of nearly 5,000 new cases per day now, compared with a low of about 1,200 new cases in March, these variants are spreading slightly fast.

For the .

2 subtype, it deserves attenti.

On April 29, data from a preprint study released by CERI showed that .

4 and .

5 were 8% and 12% faster than the Ormicon strain .

2, respective.

Compared with Omicron, .

2 has a daily growth advantage of

.

4 prevalence of nearly 70% in Gauteng, South Africa

.

5 prevalence of nearly 60% in KwaZulu-Natal, South Africa

Why are .

4 and .

5 more spreadable?

One possibility is that the .

4 and .

5 variants are better at evading immune responses, allowing them to infect people who already have immuni.

Fundamentally, these two strains can escape antibodies because of the characteristics of the F486V mutation point mentioned abo.

So, are our existing vaccines still useful for .

4 and .

5, which are so escaped?

The answer is y.

Peking University virologist Xie Xiaoliang also found that antibodies elicited by .

1 infection were less potent against .

4 and .

In layman's terms, antibodies obtained through vaccination are more resistant to the new .

4 and .

5 strains than antibodies produced by natural immunity (natural infectio.

The number of hospital admissions in South Africa is now slowly rising, but the researchers believe it is too early to tell whether .

4 and .

5 will put a lot of pressure on the healthcare syst.

Whether South Africa's high population immunity will strain the South African medical system is what we need to focus on ne.

03

.

11 strain sweeps New York, Delta strain never goes away

In addition to the .

4 and .

5 mentioned above, there is also a mutant strain .

11 from North America that is also rampa.

The researchers found that .

11 has spike mutations in the same places as .

4 and .

5 (.

4 and .

5 are spike 452R; .

11 is spike 452Q.

The emergence of these mutant strains indicates that the Omicron lineage is "evolving" by eroding immunity and gradually filling some of the loopholes in the original Omicron stra.

And the recent articles by Xie Xiaoliang and Xiao Junyu talked about the immune escape of several new "poison stars" we mentioned tod.

The study found that .

2 and its sub-strains have the strongest ACE2 receptor binding, while .

4 and .

5 have the weakest ACE2 binding (10 times lower than .

2), because the spike protein Two mutations, F486V and R493Q, a finding that suggests that .

4 and .

5 may be less efficient in spreading than .

1

But as we just mentioned above, the propagation speed of .

4 and .

5 is about 8-10% faster than that of .

2, which means that conservatively speaking, .

11 is at least higher than the existing .

2 The strains spread more than 10% fast.

Of course, the researchers also showed that "distant relatives" of the new coronavirus family cannot be ruled out to make do with this variant conference, like Alpha, Delta, and Omicron before th.

Like the Delta strain, which hasn't completely disappeared and may make a comeba.

Scientists in Israel, analyzing local wastewater and detecting traces of delta's "cryptic spread," expect infections of the mutant strain to increase during the northern hemisphere's summer, as global immunity to Omicron and his family gro.

Added, Delta's descendants may also make a comeba.

Finally, the three conclusions drawn from this article by Professor Xie Xiaoliang are attached:

In response to neutralizing antibodies produced by previous .

1 infection, Omicron can continuously evolve targeted mutations to achieve immune escape;

This continuing evolution poses a serious threat to SARS-CoV-2 herd immunity;

Vaccine booster designs based on .

1 may not provide broad-spectrum protective effica.

From the above, we can see that we cannot underestimate the mutation of the new coronavir.

In the face of the "evolving" strains all the time, the only thing we can do is to do physical protection, actively vaccinate, and look forward to the development and development of broad-spectrum vaccin.

Marketed, it can better resist the infringement of mutant strai.

References

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5 subtype, spread to another count.

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Continued Emergence and Evolution of Omicron in South Africa: New .

4 and .

5 lineag.

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https:// The epidemic in South Africa has made a comeback, with a peak every 6 mont.

Will it become the norm.

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11 .

4 and .

5 escape antibodies elicited by Omicron .

1 infecti.

https://doiorg/1021203/rs3rs-1611421/v