Prime Minister Boris Johnson said the variant could be 70 percent more transmissible.
“NERVTAG’s early analysis suggests the new variant could increase the R [reproduction number] by 0.4 or more,” Johnson said.
“Although there’s considerable uncertainty, it may be up to 70 percent more transmissible than the old variant, the original version of the disease,” he added.
“This is early data and it’s subject to review. But it’s the best that we have at the moment.”
The PM boasted “by far the best genomic sequencing ability” of the UK to identify new strains of the virus. He said that Chief Medical Officer Chris Whitty had submitted their current findings to the World Health Organisation and will continue to study the variant.
“There’s no evidence to suggest it is more lethal or causes more severe illness,” Johnson added. “Equally, there’s no evidence to suggest the vaccine will be any less effective against the new variant.”
Speaking at the same briefing, Vallance told the nation that genetic studies, frequency studies, and laboratory studies all came together to suggest this virus has a significant, substantial increase in transmissibility.
“So the new variant was first thought to have occurred sometime in mid September, in London or Kent,” he said.
“This new variant, not only moves fast, it is increased in terms of its ability to transmit,” Vallance said while presenting a slide showing the percentage of the new variant in all positive cases across time in affected areas.
The new variant “is becoming the dominant variant, it is beating all the others in terms of transmission,” he added.
Vallance said the new variant contains 23 different mutations, which is an unusually large number.
“Across the rest of the country, the Christmas rules allowing up to three households to meet will now be limited to Christmas Day only rather than the five days, as previously set out,” the PM added.