Jeffrey Barrett, a statistical geneticist at the Covid-19 Genomics UK consortium, warned there was a lag in the sequence data being sampled, so the most recent data was from the first week of December when England came out of the second national lockdown.
At a Science Media Centre briefing on Tuesday, he said: “They’re relatively small numbers but I think it is important to be aware that it is certainly not the case that this is just completely geographically constrained to what is the current Tier 4 area.”
The new variant led to London and parts of southern and eastern England being rushed into the new Tier 4 regime at the weekend, effectively cancelling Christmas plans and imposing measures similar to previous national lockdowns.
Dr Barrett said more up-to-date data from community testing also found one of the mutations of this variant.
He said: “It shows essentially the same picture, that the variant is present in very many different places in England.
“It is certainly not isolated in one place, it has begun to spread to many places in England.”
Professor Tom Connor, a genomics expert from Cardiff University, told the briefing that sequencing data shows cases around the UK, including Wales and Scotland.
He said it was no surprise that a new variant had been found in countries – including the UK, Denmark and the Netherlands – which have mature sequencing systems set up, and he believed similar variants will pop up around the world.
Prof Connor said Wales had sequenced more viruses in the past week than the whole of France during the entire pandemic.
Ravindra Gupta, professor of clinical microbiology at the University of Cambridge, told the briefing that a new variant had also been detected in South Africa, which also does a lot of sequencing.
The new variants found in the UK, South Africa, Denmark and the Netherlands led to Germany banning travel from those countries.
Sharon Peacock, director of COG-UK and a professor of public health and microbiology at the University of Cambridge, said: “We’ve sequenced 150,000 genomes which is about half the world’s data, so if you’re going to find something anywhere you’re going to find it probably here first.
“If this occurs in places that don’t have any sequencing you’re not going to find it at all.”
She said there was no evidence to suggest the new variant caused higher mortality, and no reason to believe the vaccine being rolled out in the UK will not be effective.
However, Prof Connor warned not enough time has passed to know whether the variant leads to a worse outcome for infected people.
He said: “When you’re talking about outcome you’re normally looking at 28 days after the person has been diagnosed – with a lot of these cases popping up in late December we’re not at that point where you would have that outcome information to do that analysis yet.”
Prof Gupta said the majority of people who contract Covid-19 recover, adding: “There isn’t really, in my mind, a huge rationale for thinking there’s going to be a worse outcome (with the new variant).”
Dr Barrett said 23 mutations of the virus were detected “all at once”, which is rare, suggesting it did not happen by coincidence.
He said: “It suggests that something happened – we don’t know what that something is, that produced this variant, and it doesn’t happen that often because we haven’t seen it before.
“I think the conjunction of very rapid spread and a lot of mutations makes this less and less likely to be just a coincidence.”
Judith Breuer, professor of virology at University College London (UCL), said the variant has been detected in inpatients at hospitals across the UK.