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 new strain?
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.
New data has shown it could be better at infectiong children. Professor Neil Ferguson said the new variant had a statistically significant increase among under 15-year-olds compared to other strains 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, many associated with the so-called ‘spike’ protein – the part of the virus which is responsible for binding to human cells.
This is significant because the vast majority of vaccines in development target the spike receptor. If it changes beyond recognition, the jabs will be unable to induce the necessary immune response within people.
Does this mean the vaccine will be ineffective?
Fortunately, no. The proteins that coat the shell of the virus would need to undergo significant genetic transformations to render the vaccines redundant – something that, at this stage, doesn’t appear to have happened. Analysis is still being carried out though.
"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.”
How far has the new strain spread?
For now, the new variant appears to be focused in and around the south of England.
Let’s look at the numbers. 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, the new strain is 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 some part by the highly infectious variant.
If allowed to go unchecked, the new strain could increase the country’s R rate – which is currently estimated to be between 1.1 and 1.2 – by 0.4.
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 strain?
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 strains. 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.”
This article was amended on 24.12.20. It previously referred to a potential increase in the R rate in percentage terms, which was not correct.