Scientists have identified a new variant of coronavirus which may be linked to the faster spread of COVID-19 in the South of England.


In a speech to the House of Commons on 14 December, Health Secretary Matt Hancock said there is nothing to suggest this new strain is more likely to cause serious disease, and it is "highly unlikely" that the mutation will mean the coronavirus vaccines will no longer work.

On 19 December, the Government’s chief scientific adviser, Sir Patrick Vallance, warned the new variant was becoming the dominant strain, with a rapid rise in cases in recent days. Early analysis suggests the new strain could be up to 70 per cent more transmissible than the old variant.

There have already been a number of new coronavirus strains identified since the start of the pandemic, none of which have had a detectable effect on the virus or subsequent illness.

While we know that the coronavirus is mutating, the discovery of a new, potentially more infectious strain has fuelled a lot of questions.

What is the new COVID-19 strain?

The new strain was originally named 'VUI – 202012/01' as it was the first mutation under investigation in December, however it is now being referred to as the B.1.1.7 variant.

Public Health England said that as of 13 December, 1,108 cases with this new variant had been identified, predominantly in the South and East of England.

Not enough is yet known about the new strain, so it is premature to make any claims about the potential impacts of virus mutation. But if the virus spreads faster it will be harder to control.

However, there have already been various, new strains of COVID-19 identified with no real consequence.

Should we be worried about the new coronavirus strain in the UK?

New variants of a virus are not necessarily always a bad thing – they could even be less virulent.

However, if they spread more easily but cause the same disease severity, more people will end up becoming ill in a shorter period of time.

It is thought that the B.1.1.7 variant is the first strain that will be investigated in such detail by Public Health England, possibly because it appears this particular strain is spreading quite fast in the South of England.

How fast is the new strain spreading?

Prime Minister Boris Johnson told a Downing Street briefing that early analysis showed the new strain could increase the reproductive rate by 0.4 or more and that it may be up to 70 per cent more transmissible than the old variant.

Sir Patrick said the variant, which was thought to have emerged in mid-September in London or Kent, had a “significant substantial increase in transmissibility”.

He added that by December, over 60 per cent of infections in the capital had been the new variant, saying: “It moves fast and is becoming the dominant variant.”

Covid-19 growth rates in England © PA Graphics
COVID-19 growth rates in England © PA Graphics

Will the tier system stop the spread of this new strain?

Chief medical officer Professor Chris Whitty has said that the tier system was holding cases in other parts of the country but the new variant posed a risk to tiers.

“If you have a low amount of this variant, the rate of increase is held by the tiers, but if you have a very high rate of this variant, then it is not held sufficiently by the tiers and it is going up rapidly,” he said, adding that people should not travel and risk spreading the variant around the country.

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He said there was a risk of the variant “going out to other areas of the country where it currently is not a problem”.

But he said measures such as social distancing and limiting contact were the ones to use.

Will the vaccine work against the new coronavirus variant?

Mr Hancock said the latest clinical advice is that it is highly unlikely that this mutation would fail to respond to a vaccine.

The vaccine works by showing the body a section of the virus’s genetic code, so that our immune system can mount a defence. It’s unlikely that a single change in COVID-19 would make this process less effective.

However, this could happen over time as more mutations occur, as is the case every year with flu.

Public Health England have said this newly identified variant includes a mutation in the spike protein and that changes in this part of the spike protein may result in the virus becoming more infectious and spreading more easily between people.

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Prof Whitty said in a Downing Street press conference that there was nothing to suggest a vaccine would not work against the new strain and that current tests can detect it.

“There’s still quite a small proportion of the population [who are thought to] currently have immunity due to prior infection,” said Whitty. “So there isn’t a huge selection pressure on this virus.

“And therefore, it would be surprising – not impossible, but pretty surprising – if [the new strain] would actually have evolved to be able to get around the vaccine.”

There is no evidence that the newly-reported variant results in a more severe disease
Professor Wendy Barclay, Imperial College London

To clarify, he added that selection pressures – like a vaccine, or immunity as a result of a prior infection – would mean that any new variants that emerge would be more likely to be strains that are able to evade an immune system. But the vaccine is far too new to suspect this to be the case.

Scientists will now be growing cultures of the strain in laboratories to see how it responds, to see if it produces the same antibody response to the existing strain, to see how the vaccine might impact it and to get a full picture of what it means.

However, it may take up to two weeks to investigate thoroughly.

Are there different symptoms between coronavirus strains?

Whitty also said there was nothing to indicate the new strain causes any different symptoms, that the testing is different or the clinical outcome is different for this variant.

“The main reason we are raising this to people’s attention is the question about whether this is spreading more quickly,” said Whitty. “It may be 'cause and effect', or it may not.”

Most mutations that arise and spread have no detectable effect on the biology of the virus. But a few have the potential to change both the biological behaviour of the virus and persist if they confer an advantage to the virus.

Which coronavirus strain is most deadly?

There have been many mutations in the coronavirus since it emerged in 2019. There are currently around 4,000 mutations in the spike protein gene.

“SARS-CoV-2 is an RNA virus and mutations are expected to occur as it replicates,” said Professor Wendy Barclay, head of the department of infectious disease, Imperial College London. “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.”

“There is no evidence that the newly-reported variant results in a more severe disease.”

Read more about coronavirus:

The COVID-19 Genomics UK (COG-UK) consortium said it is difficult to predict whether any given mutation is important when it first emerges, and that it would take “considerable time and effort to test the effect of many thousands of combinations of mutations”.

Other virus strains known to scientists include the D614G variant, which was previously detected in western Europe and North America. D614G is believed to spread more easily but not cause greater illness.

The Danish government culled millions of mink after it emerged that hundreds of COVID-19 cases in the country were associated with SARS-CoV-2 variants associated with farmed minks — including 12 cases with a unique variant, reported on 5 November.


In October a study suggested that a coronavirus variant that originated in Spanish farm workers spread rapidly throughout Europe and accounted for most UK cases. This variant, called 20A.EU1, is known to have spread from farm workers to local populations in Spain in June and July, with people then returning from holiday in Spain most likely playing a key role in spreading the strain across Europe.


Amy ArthurEditorial Assistant, BBC Science Focus

Amy is the Editorial Assistant at BBC Science Focus. Her BA degree specialised in science publishing and she has been working as a journalist since graduating in 2018. In 2020, Amy was named Editorial Assistant of the Year by the British Society of Magazine Editors. She looks after all things books, culture and media. Her interests range from natural history and wildlife, to women in STEM and accessibility tech.