Updated: December 22, 2020 8:43:46 am
Flights from Great Britain are canceled at Cointrin Airport, in Geneva, Switzerland, on December 21, 2020 (Reuters Photo: Denis Balibouse)
Monday India suspended all flights to and from the UK through December 31, amid concerns over a new variant of SARS-CoV-2 that is “spreading and growing rapidly” there. Several other countries have also suspended UK flights and imposed travel restrictions.
What are these concerns that create travel restrictions?
Last week, it was revealed that the new SARS-CoV-2 variant was the reason behind the rapid increase in Covid-19 cases in the south and east of England. It is known as VUI (Variant Under Investigation) 202012/01, or the B.1.1.7 lineage.
“In recent days, thanks to our world-class genomic capabilities, we have identified a new variant of the coronavirus, which may be associated with the more rapid spread in southern England,” said UK Health Secretary Matt Hancock , to the House of Representatives. commons on December 14. UK authorities have already notified the World Health Organization about the variant.
Public Health England (PHE) announced that 1,108 cases with this variant had been identified as of December 13, “predominantly in the south and east of England.” “PHE is working with partners to investigate and plans to share its findings over the next 2 weeks,” he said.
How is the variant?
The variant was identified in genomic surveillance by COVID-19 Genomics UK (COG-UK), a consortium analyzing UK genome sequencing data. COG-UK is the largest contributor to the global Covid-19 GISAID database.
The variant is the result of multiple mutations in the spike protein of the novel SARS-CoV-2 coronavirus, as well as mutations in other genomic regions of the RNA virus. Preliminary analysis suggests that it is more transmissible than previously circulating variants. COG-UK identified one of these mutations as “N501Y”, in an area of the spike protein that binds to a key protein in the human cell, the ACE2 receptor. This was an indication that the alterations can theoretically make the virus more infectious. “Efforts are underway to confirm whether or not any of these mutations are contributing to increased transmission,” the consortium said.
What do we know so far about the transmissibility and severity of the disease?
On Sunday, PHE said that data from whole genome sequencing, epidemiology and modeling suggest that the new variant “is more easily transmitted than other strains.”
However, he also stressed that “there is no evidence” that the variant is more likely to cause serious illness or mortality. “… But we are continuing research to understand this better,” he said. He said mortality is a “lagging indicator” and that he will “continuously monitor this for the next several weeks.”
PHE has said that it does not yet know the mechanism for this increase in transmission. “We know that mutations in the spike protein, the part of the virus that makes it infectious, can change the way the virus interacts with human cells,” he said.
He said that evidence shows that infection rates in geographic areas where this particular strain has been circulating have increased faster than expected, and model evidence has shown that this variant has a higher transmission rate than other variants in current circulation.
A police officer directs traffic at the entrance to the closed ferry terminal in Dover, England, on Monday, after the port of Dover was closed. (AP Photo)
How important is increased transmissibility?
On December 18, the New and Emerging Respiratory Virus Threat Advisory Group (NERVTAG), which advises the UK government on the threat posed by new and emerging respiratory viruses, said the new variant could potentially increase the number of reproduction of the disease up to 0.93. . He said he has “moderate confidence” that the new variant “demonstrates a substantial increase in transmissibility compared to other variants.”
However, the expert body concluded that “there is currently insufficient data to draw any conclusions” about the underlying mechanism of increased transmissibility, “the age distribution of cases, and the severity of the disease. they have identified 4 deaths in around 1,000 cases, but “more work is needed to compare this mortality rate with comparable data sets.”
“The location of the mutations in the receptor-binding domain of the spike glycoprotein raises the possibility that this variant is antigenically distinct from previous variants. Four probable reinfections among 915 subjects with this variant have been identified, but more work is needed to compare this reinfection rate with comparable data sets, ”he said.
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On Sunday, a threat assessment report released by the European Center for Disease Prevention and Control said that phylogenetic analysis reveals that the “group differs by 29 nucleotide substitutions from the original Wuhan strain.” “Three sequences from Denmark and one from Australia, from samples collected in November 2020, are grouped with the UK variant, probably indicating that there has been international spread, although the extent remains unknown,” he said.
The port of Dover closed due to EU countries imposing a travel ban from the UK, following the spread of a new strain of Covid (Reuters Photo).
But hasn’t the virus mutated before?
Whenever a virus replicates and circulates in a human population, mutations occur naturally, at a rate of about one to two mutations per month in the global phylogeny.
In fact, for SARS-CoV-2, COG-UK says that there are currently around 4,000 mutations in the spike protein. The D614G variant was previously the dominant strain because it spread so easily. Another strain that originated in Spanish agricultural workers, 20A. EU1, spread rapidly across Europe in summer.
“It is difficult to predict whether a given mutation is important when it first arises, in a context of continual emergence of new mutations. Understanding its importance may be possible based on experimental work showing a link between the mutation and a subtle change in the biology of the virus. However, it would take a lot of time and effort to test the effect of many thousands of combinations of mutations, ”said COG-UK.
Will it impact the development and response of the vaccine?
On Sunday, UK authorities said more lab work is underway as a priority to understand this. “There is currently no evidence to suggest that the Pfizer vaccine would not protect people against the new strain,” PHE said.
© The Indian Express (P) Ltd
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