A mutation of the "British strain" COVID-19 has been described. How is it dangerous, besides infectiousness?

What is the “British” strain of coronavirus?

Strain 202012/01 is a strain of the SARS-CoV-2 virus that causes COVID-19. This

the strain was first discovered in early December 2020 during the UK pandemic. The earliest samples with the detected strain were collected on September 20.

By mid-December the strain began to rapidlyspread. This correlates with a significant increase in the rate of COVID-19 infections in the UK; this increase is believed to be at least in part due to the N501Y mutation within the receptor-binding domain of the spike glycoprotein, which binds to the ACE2 receptor in human cells.

The strain is also notable for a large number of mutations compared to the known SARS-CoV-2 mutation trend as of December 2020.

The strain is known by several names. It is commonly referred to as the "UK strain of COVID-19" and the "UK strain of coronavirus" in government communications and in the media.

This strain was previously called "the first strainunder review in December 2020 (VUI - 202012/01) by Public Health England, but was downgraded to a Strain of Concern by Meera Chand and colleagues in a report published by Public Health England on 21 December 2020.

In a report written on behalf of the ConsortiumGenomics COVID-19 UK (COG-UK) Andrew Rambeau and his co-authors referred to this strain as lineage B.1.1.7. The CDC also calls this strain 20B / 501Y.V1.

Countries with confirmed cases of VOC-2020/12/01

Where did he come from?

Apparently from South Africa.The first report on this strain was published by a group of local biologists led by da Oliveira on December 22, 2020 - samples were collected in early October. Since not all countries have surveillance programs for new strains, the very first detection in a country does not, of course, prove that a variant originated in the exact location where it was found.

Properties of the “British” strain

  • Genetics

Mutations in the SARS-CoV-2 virus happen quiteOften: According to the COVID-19 Genomics Consortium of Great Britain (COG-UK), more than 4,000 mutations have been found in the spike glycoprotein alone in different strains of this virus.

The VOC-202012/01 strain is defined by 23 mutations: 13 nonsynonymous mutations, 4 deletions, and 6 synonymous mutations (i.e. 17 mutations change proteins, and 6 do not).

  • Transmissibility

British scientific advisory body NERVTAG(Advisory Group on New and Emerging Respiratory Viruses) concluded on December 18, 2020 that they have moderate confidence that VUI-202012/01 is significantly more transmissible than other strains, with data not yet sufficient to make definitive conclusions about the underlying mechanism of increased transmissibility. 

Data obtained by NERVTAG showed that thisstrain has a "selection coefficient" of 0.70 (70%), assuming a generation interval of 6.5 days. Later work used the relative number of reproductions as a measure, which is an indicator of the coefficient of selection.

Based on slightly different data, the relative number of reproductions (“multiplicative advantage”) was determined to be 1.74 (this means that this strain is 74% more transmissible).

This strain has become dominant in London, andin the east and southeast of England for one to two months. Similar rapid growth has been observed in Ireland, and it appears that this strain will soon become dominant there as well.

The US is supposed to do the samein March. The surge in SARS-CoV-2 infections early in the new year is seen as a result of the strain's increased transmissibility, while the incidence of other strains is declining. This requires tighter limits to avoid a rapid exponential increase in infections. Transmission control of this strain, in turn, looks increasingly weak.

First image of a British strain of the virus

Are vaccines effective against it?

Several COVID-19 vaccines have been developed in the past.

However, as more happensmutations, the vaccine may need to be modified. SARS-CoV-2 does not mutate as quickly as influenza viruses, for example, and the new vaccines that were proven effective by the end of 2020 are types that can be modified if necessary.

As of the end of 2020, bodieshealth experts and experts from Germany, the United Kingdom and America believe that existing vaccines will be as effective against the VOC-202012/01 strain as against the previous strains.

On December 18, 2020, NERVTAG concluded that "there are currently insufficient data to draw any conclusion about the insensitivity of this strain to vaccine antigens."

So far public health serviceThe UK has confirmed that there is “no evidence” that the new strain will be resistant to the Pfizer-BioNTech vaccine currently being used in the UK vaccination program, so vaccinated people are still protected.

What is special about the “British” strain?

In general, the "British" strain has 29 mutations incompared to the original Wuhan strain. This suggests that it mutates much faster than the latter, for which virologists have recorded approximately two mutations per month.

Moreover, many mutations found in the proteinthorns of the new strain, facilitate the binding of the virus to the receptors of the host cells. Therefore, scientists suggest that strain B.1.1.7 will be more dangerous - it will have a higher virulence, and, possibly, the ability to evade the action of the developed vaccines.

In a new study, the authors decided usingcomputer simulations to predict how different mutations of the "British" strain will affect the rate of spread and severity of infection, as well as the replication and pathogenesis of the virus itself.

To explain the unusually high frequency of mutations occurring in both the S spike protein and the N-terminal domain, the researchers offer three explanations:

  • long-term infection with the virus in a patient with a weakened immune system allowed the virus to mutate at a high rate;
  • adaptive mutations began in animal hosts, were transmitted to humans through zoonotic transmission and continued in the human host;
  • selective selection that occurs in the structure of the virus under pressure from antibodies.

The simulation results showed thatthe stability of hydrogen bonds in the mutant variant is higher. Its spike protein also makes more bonds with the receptor of host cells, and these bonds persist for a longer time. The estimated transmission rate of strain B.1.1.7 is 70% higher and the number of reproductions is 0.4 higher than that of the classical variant.

The danger, according to the authors, also lies inthat by testing standards, reverse transcription polymerase chain reaction, or RT-PCR, may not recognize the viral RNA of the new strain. Also, a mutation-altered strain may allow it to evade neutralization by antibodies and reduce the effectiveness of vaccines.

Where is it distributed?

Now - practically all over the world.According to the data of the largest database of genomes GISAID, most of the corresponding samples were found in the UK, Denmark, USA, France, Spain and Ireland, there are genomes even from such relatively prosperous countries as New Zealand and Singapore. The distribution maps can be viewed here.

With the presence of the strain in Russia, the situation is not entirelyclear. On January 10, Anna Popova reported about its discovery in the country. However, in the largest open international database GISAID of genomes of variant B.1.1.7. from Russia no.

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