New coronavirus strain up to 70% more transmissible, government says

New Covid variant in the UK: Everything we know so far

New variant does not cause more serious disease or higher rates of mortality, government says

Samuel Lovett@samueljlovett
Tuesday 22 December 2020 12:55
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The government has announced that the newly identified variant of coronavirus is up to 70 per more transmissible than the original form of the pathogen.

This has led to a surge in cases and hospitalisations across London, the south and the southeast, with the government forced to introduce a new series of restrictions that will attempt to halt the spread of Covid-19.

So, what do we know about the variant?

This version of the virus spreads far more easily between people as a result of a series of mutations that have been identified in the pathogen’s genetic coding. It is not, however, believed to cause more severe Covid disease or higher rates of mortality.

Due to its highly infectious nature, the new variant, called VUI 202012/01, could increase the country’s R rate by 0.4 per cent if allowed to spread unchecked, the UK government has said.

Scientists have said it could also be better at infecting children. Professor Neil Ferguson said there has been a statistically significant increase in cases linked to this variant among under 15-year-olds compared to other mutated versions of the virus. This is being investigated.

Sir Patrick Vallance, the government's chief scientific adviser, said analysis showed that the variant contains 23 different genetic changes.

Some of these mutations are “silent” and don’t have any function, but “crop up and come along for the ride”, says Dr Jeffrey Barrett, lead Covid-19 statistical Geneticist at Wellcome Sanger Institute.

Others are significant and change the biology of Sars-CoV-2, altering the sequence and shape of certain proteins that make up the virus.

One of these mutations, known as N501Y, sits in the so-called ‘spike’ protein – the part of the virus which is responsible for binding to human cells.

The mutation, according to the scientists, has increased the ability of the spike receptor to attach to certain proteins that cover our own cells, therefore making it more infectious. 

A second notable mutation, named 69-70del, leads to the loss of two amino acids in the spike protein and the evasion of the immune response in some immunocompromised patients, evidence shows.

Both mutations have already been detected in other variants of Sars-CoV-2 across the world.

"These mutations haven’t just suddenly appeared out of thin air in the UK," Dr Julian Tang, a virologist at the University of Leicester, told The Independent. “The individual mutations were circulating separately, globally, for some time before combining.”

He said that the two mutations on their own weren’t too problematic, but appeared to have “combined to make up this latest 'fast-spreading' variant".

Dr Tang explained that the N501Y mutation has been circulating in different forms of Sars-CoV-2 since April, while 69/70del has been detectable as far back as January in cases in Thailand and Germany.

What does this mean for the vaccines?

All current evidence suggests the vaccines remain effective.

It’s true that the vast majority of vaccines in development target the spike receptor of the virus. If it changes beyond recognition due to mutations, the jabs may be unable to induce the necessary immune response within people.

However, the proteins that coat the shell of Sars-CoV-2 would need to undergo significant genetic transformations to render the vaccines redundant – something that, at this stage, doesn’t appear to have happened. 

Of the 23 mutations identified in the new variant, only a handful concern the virus’ spike protein. Scientists have insisted there are many other components to its structure that will still be targeted by the antibodies and T-cells induced by the vaccines.

"Our working assumption from all the scientists is that the vaccine response should be adequate for this virus," Sir Patrick Vallance, the government's chief scientific adviser, said during Saturday’s briefing. "We need to keep vigilant about this."

Daniel Altmann, a professor of Immunology at Imperial College London, said that the immune response induced by the Covid-19 jabs “would be unchanged by the mutations – so the vaccines will still work.”

Professor Ugur Sahin, who developed the BioNTech-Pfizer jab, said “it is highly likely that the immune response by this vaccine also can deal with the new virus variants.”

He admitted that "we don't know at the moment if our vaccine is also able to provide protection against this new variant", but because the proteins that coat the outside of the virus are 99 per cent the same as the prevailing mutated versions, BioNTech has "scientific confidence" in its jab.

How far has the new variant spread?

VUI 202012/01 was first identified in October from a sample taken the month before, according to Public Health England (PHE).

Online lab records suggest the first detected case of the virus was picked up in the government's Lighthouse Lab in Milton Keynes on 20 September, while PHE said on Saturday that the person who provided the swab was from Kent.

After the first official records of the virus were noted, progress was slow, and it wasn't until England's second wave took hold in late October that cases exploded.

At the time the first sample was recorded, the UK was averaging just 3,700 positive tests per day. By the start of November, the average number of positive results had jumped to 23,000 per day.

By the middle of the same month, it is thought to have caused roughly 28 per cent of cases in London and other parts of southeast England, said Chris Whitty, England’s chief medical officer.

Up to 9 December, the mutated virus accounted for:

  • 43 per cent of cases and 28 per cent of hospitalisations in the Southeast
  • 59 per cent of cases and 38 per cent of hospitalisations in the East
  • 62 per cent of cases and 34 per cent of hospitalisations in London

In contrast,  VUI 202012/01 so far been linked to just five per cent of recent cases in Yorkshire.

Generally speaking, case rates across the UK increased by more than 50 per cent between 29 November and 13 December, driven in part by the highly infectious variant.

Why has the virus mutated?

Viruses change all the time – and this one is no different. “The coronavirus has mutated many times over the last year,” said Simon Clarke, associate professor in cellular microbiology at the University of Reading.

Jonathan Stoye, a virologist at the Francis Crick Institute in London, explained that variations typically arise in viruses as “a result of errors in copying viral genetic material”. This, he said, leads to small changes in virus proteins – such as the spike receptor.

The transmission of a virus between different species also helps to fuel changes in a virus’ genetic coding – a development we’ve already seen take place in Sars-Cov-2 after it jumped into minks and then back into humans in Denmark.

And general pressures on the pathogen, such as the emergence of a vaccine or lack of available hosts, can bring about advantageous evolutions that allow it to adapt and survive.

Wendy Barclay, head of the department of infectious disease at Imperial College London, said: “Mutations are expected to occur as [the virus] replicates.  

“Some variants with changes in the spike protein have already been observed as the virus is intensely sequenced here in the UK and around the world.”

How have scientists reacted to the new variant?

John Edmunds, professor in the Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, said:

“It looks like this virus is significantly more infectious than the previous variants. This means that to control it we are going to have to put in place much more restrictive measures. I am sorry to say that it looks like there are tough times ahead, but the faster and more decisively we act the quicker we can begin to control this new virus.”

Paul Hunter, professor in Medicine, The Norwich School of Medicine, University of East Anglia, said:

“It is inevitable that this new variant will spread throughout the UK and we can expect to see increased transmission rates in all regions and devolved administrations over coming weeks.”

Ravindra Gupta, professor of Clinical Microbiology, University of Cambridge, said:

“The variant has a number of concerning mutations that mean we should control transmission through social restrictions whilst we work to learn more about the impact of these mutations on how the virus behaves. We should seriously consider regional targeting of the vaccine to control spread.”

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