The most concerning changes with the omicron variant have happened to the spike protein, where there are about twice as many mutations as the delta variant.
When Dr Tom Peacock, a virologist at Imperial College London, spotted the mutations in the sequence data last week, he labelled them “horrific” and “really awful”.
“I would take a guess that this would be worse antigenically than nearly anything else about,” he said.
‘Causing real concern’
One senior UK health official said that the spike protein on the omicron variant was “so dramatically different” that it was “causing real concern”.
“It is the worst variant I have seen so far. We have protein experts and virologists who are all extremely concerned,” the official said.
Variant first found in Botswana
The variant was first spotted in Botswana on November 11, and cases have now been found in South Africa, Israel, Germany, Italy, Belgium and Hong Kong.
The first UK cases of the omicron Covid variant were also confirmed on Saturday, with two people, in Essex and Nottinghamshire, testing positive for the variant. Officials have since started carrying out mass testing in affected areas to identify further cases.
Prime Minister Boris Johnson announced on November 27 that new restrictions would be imposed in response to the cases in a bid to slow the omicron variant.
Mr Johnson said that, from Monday, people must wear masks in shops and on public transport. Anyone who enters the UK must now also take a PCR test by the end of the second day after arrival and self isolate until they have a negative result.
Variant has 50 mutations
The variant has about 50 mutations, with 30 in the spike protein and 10 in the receptor binding motif, the part that binds to our cell receptor called ACE2, which is greater than any other mutated strain.
Spike proteins are little grappling hooks on the surface of the virus which it uses to latch on to human cells.