Coronavirus New Variant : B.1.1.7 | UPSC

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.

• 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.

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

• 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.

• 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.

• 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.

• 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.

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.

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