Since its appearance, Sars-CoV-2 has mutated many times. A new variant of the virus has recently been discovered in England. Is this strain more virulent? Is it likely to make the disease worse? Can she be resistant to the anti-Covid vaccine? Explanations.

All viruses, including Covid-19, experience several mutations. As proof, a new variant of Sars-CoV-2 has been detected in the United Kingdom. According to the British government, this strain has grown rapidly in parts of England in recent days. “We have currently identified more than 1,000 cases of Covid-19 caused by this variant, mainly in the south of England, although cases have been identified in almost 60 different local authorities,” said the Secretary of Health , Matt Hancock, before the House of Commons on December 14.

What do we know about this new SARS-CoV-2 variant?

It’s been snappily named VUI-202012/01 (the first “Variant Under Investigation” in December 2020) and is defined by a set of 17 changes or mutations. One of the most significant is an N501Y mutation in the spike protein that the virus uses to bind to the human ACE2 receptor. Changes in this part of spike protein may, in theory, result in the virus becoming more infectious and spreading more easily between people.

How was the variant detected?

It was picked up by the Covid-19 Genomics UK (COG-UK) consortium, which undertakes random genetic sequencing of positive covid-19 samples around the UK. The consortium is a partnership of the UK’s four public health agencies, as well as the Wellcome Sanger Institute and 12 academic institutions.

Covid-19: is this variant of the virus identified in England more dangerous?

This strain is cause for concern. Many wonder if this mutation made Covid-19 more infectious or more virulent. To understand this mutation of the virus, British scientists have opened an investigation into this new variant. Matt Hancock also said that the World Health Organization (WHO) had been informed of this discovery.

He told Members of the House of Commons that an “exponential” rise in Covid-19 infections was seen last week in London, Kent and parts of Essex and Hertfordshire. According to the Secretary of Health, this strain “could be associated with a faster spread (of the virus) in the south-east of England. (…) The first analyzes suggest that this variant is spreading faster than the existing variants. . “

But he wants to be reassuring. Matt Hancock explained that “there is currently no indication that this variant is more likely to cause serious illness.” According to Professor Alan McNally, an expert at the University of Birmingham, there is no evidence that this mutation made the virus more dangerous. “Let’s not be hysterical. That does not mean that it is more transmissible, more infectious or more dangerous,” he told the BBC.

The President of the French Scientific Council, Jean-François Delfraissy, also called for caution as to the potential consequences on the contagiousness and virulence of this variant of the virus. “Since March, the coronavirus has experienced multiple small mutations, but so far none of these variants have made the disease more serious. The fear is a real mutation of the Spike protein, that is- that is to say the one that allows the virus to hang on. Now, the one described by the English is about this protein, and data suggests that the virus is more infectious. This needs to be confirmed. I am not worried because we have already raised this type of alert: remember the recent fears on minks, “he developed in Paris.

Will the vaccine still work?

The new variant has mutations to the spike protein that the three leading vaccines are targeting. However, vaccines produce antibodies against many regions in the spike protein, so it’s unlikely that a single change would make the vaccine less effective.

Over time, as more mutations occur, the vaccine may need to be altered. This happens with seasonal flu, which mutates every year, and the vaccine is adjusted accordingly. The SARS-CoV-2 virus doesn’t mutate as quickly as the flu virus, and the vaccines that have so far proved effective in trials are types that can easily be tweaked if necessary.

Peacock said, “With this variant there is no evidence that it will evade the vaccination or a human immune response. But if there is an instance of vaccine failure or reinfection then that case should be treated as high priority for genetic sequencing.”


BMJ 2020;371:m4857


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