Coronavirus New Variant : B.1.1.7 | UPSC

Coronavirus New Variant : B.1.1.7 | UPSC

      HEADLINES:

Coronavirus new variant: Genomics researcher answers key questions

      WHY IN NEWS:

The new variant is touted to be responsible for an increasing proportion of cases in parts of the United Kingdom

SYLLABUS COVERED: GS 3:Health:Diseases

      LEARNING: 

For PRELIMS it is important to understand the new variant and its specifications.

For MAINS collect the harmful impacts of new variant and this will help you in tracing the evolution of COVID-19 pandemic .

      ISSUE: 

A new variant of SARS-CoV-2, the virus which causes COVID-19, is thought to be driving increased transmission of the disease in parts of the United Kingdom.

  • The government has placed some regions including London under new, stricter coronavirus restrictions, known as Tier 4.
  • People in Tier 4 areas will not be able to gather with anyone outside their household for Christmas, while those in the rest of the country can only gather on Christmas Day itself.

THE NEW VARIANT : VUI–202012/01 or  B.1.1.7

  • The new variant could increase transmission of COVID-19 by as much as 70 per cent and increase the R or reproduction number by 0.4.

WHAT DO WE KNOW ABOUT THIS NEW VARIANT?

  • The new UK variant, known as VUI–202012/01 or lineage B.1.1.7, was first announced by the health secretary on December 14.
  • It was subsequently confirmed by Public Health England and the UK’s COVID-19 sequencing consortium.

The variant carries 14 defining mutations including seven in the spike protein, the protein that mediates entry of the virus into human cells. 

  • This is a relatively large number of changes compared to the many variants we have in circulation globally.
  • To date, genetic profiles, or genomes, of this variant have been largely sequenced .
  • There have also been reports of a case in the Netherlands,Denmark and Australia.

IS IT MORE DANGEROUS?

  • There was no evidence to date that this variant alters disease severity, either in terms of mortality or the seriousness of the cases of COVID-19 for those infected.
  • Work is underway to confirm this.

HOW DO VIRUS MUTATIONS HAPPEN?

  • Mutations are a natural part of virus evolution.
  • In the case of SARS-CoV-2, these mutations may arise due to random errors during virus replication.

This can be induced by antiviral proteins within infected people, or via genetic shuffling, known as recombination. 

  • Though signs of recombination are not currently detected in SARS-CoV-2.

Most viral mutations are expected to have no impact.

  • However, every so often a mutation, or in this case a particular combination of mutations, may strike lucky and offer the virus a new advantage.
  • Viruses carrying these combinations of mutations may then increase in frequency by natural selection given the right epidemiological environment.

WHERE DID THE VARIANT COME FROM?

  • To date, scientists have not identified any closely related viruses to support the theory that the variant had been introduced from abroad.

The patterns of mutations observed are more supportive of an extended period of adaptive evolution most likely in the UK based on current data.

  • Similar patterns of mutation to these have been observed in the evolution of SARS-CoV-2 in chronically infected patients with weaker immune systems.
  • The current hypothesis is that such a scenario of chronic infection, in a single patient, may have played a role in the origin of this variant.

HOW MANY VARIATIONS OF SARS-COV-2 HAVE WE FOUND?

  • There are many thousands of lineages of SARS-CoV-2 which differ on average by only a small number of defining mutations.

It remains true that SARS-CoV-2 currently in global circulation have little genomic diversity.
 

  • Subtleties in the mutations carried in different lineages can, however, be very useful for reconstructing patterns of transmission.

WHY IS THIS ONE DIFFERENT?

  • It is important to note that many of the mutations defining the UK variant have been observed in SARS-CoV-2, quite early in the pandemic.
  • Yet the UK variant, or lineage, is defined by an unusual number and combination of mutations.

One of these mutations, N501Y, has previously been shown to increase binding of the virus to receptors in our cells.

  • N501Y was first sequenced in a virus in Brazil in April 2020.
  • It is currently associated with a SARS-CoV-2 variant also rising in frequency in South Africa – an independent lineage from B.1.1.7 that is also warranting concern.

Coronavirus New Variant : B.1.1.7

The new variant is thought to be driving rates of transmission in the UK.

  • The particular deletions identified in the spike protein of B.1.1.7 have appeared in multiple other lineages of the virus at increasing frequency.
  • It was also observed in chronic infections where they may alter antigenicity, recognition by immune antibodies.
  • B.1.1.7 also harbours a truncated ORF8 gene, with deletions in this region previously associated with decreased disease severity.
  • The functional effect of these mutations and deletions are still to be determined.

WHAT DOES THIS MEAN FOR THE VACCINE?

  • At the moment scientist are puzzled.
  • Research workers should be reassured that vaccines stimulate a broad antibody response to the entire spike protein.

Thus the vaccines efficacy will not be significantly hampered by mutations. 

  • However, there is an increasing body of evidence that other species of seasonal coronaviruses exhibit some ability to escape immunity over longer time periods.

      IASbhai WINDUP: 

  • It is therefore conceivable that we may reach a point where we are required to update our COVID-19 vaccines, as we do for influenza, to reflect the variants in circulation at the time.
  • It’s too early to say if this will be the case now, but extensive genome sequencing, data sharing, and standardised reporting of variants will be vital to inform these efforts.The Conversation
SUGGESTED READING : NAMING OF CORONAVIRUS 
     SOURCES:  THE HINDU | Coronavirus New Variant : B.1.1.7 | UPSC

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