Meanwhile Parliament has been told it is likely the new variant probably started in one person in Kent. Speaking during an evidence session of the Commons Science and Technology Committee on Wednesday morning, Professor Peter Horby, chairman of the New and Emerging Respiratory Virus Threats Advisory Group (Nervtag), said scientists were still exploring whether the new mutant coronavirus strain could sidestep immunity caused by vaccine or prior infection.
He said: “What we don’t know yet is if there’s any difference in the severity of disease, the age distribution of cases, or most importantly whether there is any immune escape.”
Prof Horby also said the strain likely started from one person in Kent, and could have been caused by “random errors” when the virus copies.
There were a number of possible reasons why the mutant strain of the virus appeared to be spreading faster than others, he added.
He told the Commons Science and Technology Committee: “The underlying mechanism is not fully clear – it could be because the virus replicates faster, which means you get higher viral loads which means you are more infectious.
“It could be that it takes a shorter time between being exposed and being infectious – if that timeframe shortens you get quicker transmission.
“Or it could mean the duration of infectiousness is longer.”
Prof Horby also denied any suggestion that Prime Minister Boris Johnson had overstated the transmission rates of the mutant strain in order to cancel Christmas.
He said: “I don’t think there’s been any ‘egging up’, as far as I can tell. This is a new variant which is of concern.”
Asked if a lax attitude towards lockdown measures could have caused the mutant strain to spread, Nervtag member Professor Neil Ferguson said corroboration of other data suggested otherwise.
He said: “There was nothing special about what was going on in Kent and the south of England during lockdown compared with other areas of the country.
“We saw the non-variant decline in a particular week and place, whilst the variant increased in the same week and place in the same population.”
(More to follow)