At first, scientists said there was no evidence it is more deadly.
Professsor Chris Whitty said in December: “There is no current evidence to suggest the new strain causes a higher mortality rate or that it affects vaccines and treatments although urgent work is underway to confirm this."
Experts did say it may be responsible for the "faster spread" of the virus in London and the south-east in the final weeks of 2020 and at the star of January.
But today, the government’s chief scientific adviser, Sir Patrick Vallance, said the strain may be more deadly than the original.
He said on Friday while there was a “lot of uncertainty” around the data, it was a matter “of concern” that as well as spreading more quickly, the mutant strain could also lead to more deaths.
The expert also gave the grave warning that certain evidence suggested the covid-19 variants from South Africa and Brazil may be less susceptible to approved vaccines.
Here we answer some questions about the developments:
- What did Sir Patrick confirm?
Sir Patrick suggested the new variant could increase the mortality rate by nearly a third for men in their 60s who have Covid-19.
For a thousand people in that group who became infected with the old variant, roughly 10 would be expected to die – whereas with the new variant it might be 13 or 14, with similar increases in mortality rates across the age ranges.
“I want to stress that there’s a lot of uncertainty around these numbers and we need more work to get a precise handle on it, but it obviously is of concern that this has an increase in mortality as well as an increase in transmissibility, as it appears of today,” he said.
- What did he say about the South Africa and Brazilian strains and how they respond to approved vaccines?
Sir Patrick said that while there was growing evidence that the vaccines would be effective against the UK variant, there was uncertainty over how well it would work against those from South Africa and Brazil.
“We know less about how much more transmissible they are. We are more concerned that they have certain features that might (make them) be less susceptible to vaccines.
“They are definitely of more concern than the one in the UK at the moment, and we need to keep looking at it and studying it very carefully.”
He stressed the evidence remained uncertain and that there was no sign the South African or Brazilian variants had any “transmission advantages” over those in the UK and so would not be expected to spread more quickly or “take over”.
Earlier, footage emerged of an online briefing by Health Secretary Matt Hancock for travel industry executives in which he suggested the South African variant could reduce the efficacy of the vaccines by about 50%.
“If we vaccinated the population and then you got in a new variant that evaded the vaccine – then we’d be back to square one,” he said.
- Is there any indication when we might get out of lockdown?
No. England’s chief medical officer Professor Chris Whitty said that while infections were falling and hospital admissions were beginning to “flatline” – the situation across the country remained “extremely precarious”.
“A very small change and it could start taking off again from an extremely high base,” he said. “If that happened again, we would be in really, really deep trouble.”
The latest Government figures showed a further 1,401 people had died within 28 days of testing positive for Covid-19 as of Friday, bringing the UK total to 95,981.
Prof Whitty warned it would be some weeks before there was a fall in the numbers of hospitalisations, while the peak of deaths “may well be still in the future”.
Mr Johnson said there could be no easing of the lockdown restrictions in England until it was clear the vaccination programme was working.
Earlier scientists advising the Government said the reproduction number – the R – for coronavirus has fallen to below 1 across the UK, suggesting a retreating epidemic.
- Are mutations in viruses unusual?
There have been many mutations in the virus since it emerged in 2019.
This is to be expected – SARS-CoV-2 is an RNA virus and these viruses mutate and change.
Public Health England (PHE) said that, as of December 13, 1,108 cases with this new variant had been identified, predominantly in the south and east of England.
It has been named VUI – 202012/01 – the first variant under investigation in December.
- Are new variants always a bad thing?
Not necessarily. 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.
- Is it the first novel strain detected in the UK?
A number of variants have been detected using sequencing studies in the UK.
A specific variant (the D614G variant) has previously been detected in western Europe and North America which is believed to spread more easily but not cause greater illness.
But it is thought this is the first strain that will be investigated in such detail by PHE.
- What examples are there of other virus strains other than the UK, South Africa and Brazil variants?
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 November 5.
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.
The 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.