Quarantine and self-isolation rules could be reviewed if mutant variants prove to be infectious for longer, a top official has suggested.
Dr Jenny Harries addressed whether isolation length times could change during Wednesday night's Downing Street press conference after a fresh study showed some strains appeared to linger longer in the body.
England's deputy chief medical officer told the briefing officials were looking closely at new studies that suggest some people remained infectious with the Kent coronavirus strain for up to 13 days.
Scientists from top US universities, including Harvard and Yale, found it can take the body's immune system almost 30% longer to clear an infection with the variant.
The strain is now dominant in the UK after it began ripping around the country shortly before Christmas, and was blamed for driving up deaths and cases in the second wave.
The latest research has not yet been peer reviewed, but has led to questions about whether isolation protocols could be reviewed due to the virus' mutations.
Current official quarantine and self-isolation times are modelled on the eight-day infectiousness period of the original variant.
Dr Harries said experts were monitoring mutant variants that have emerged in the UK.
But she stressed it is not yet known whether the virus is actually still infectious for the entire period its presence can be detected in someone's body.
She told last night's No10 briefing: "We look at the different variants regularly, we have variants of interest and variants of concern, those are being monitored.
"You'll be aware that the UK has probably the best genomics functionality in the world.
"Different studies will come out with slightly different periods, and what you will have seen with the original coronavirus in the UK is that we manage the length of time for quarantine to minimise the inconvenience to individuals but still reduce the risk of onward infection.
"And so, yes we are looking at this, but we need to be really careful just because as with the original coronavirus... the time you detect the virus doesn't mean necessarily that it is the infectious period."
But Dr Harries noted experts would consider the role of the vaccine rollout in any future questions about isolation length times, as officials monitor how well the jab is working to stop the spread of the virus overall.
It comes as the UK enters its second week of mandatory hotel quarantine for people returning from 'red list' countries.
Travellers returning from areas on the list must pay for their own 10-day isolation stay when they enter the UK.
