Mutant Covid: how dangerous is the new strain of coronavirus?

The new coronavirus variant that put London and Southeast England into lockdown and cut off transport links with mainland Europe is thought to be about 70% more infectious than previous dominant strains.

Where is it?

The rapidly spreading strain is understood to have originated in Kent and “has been suggested as one reason why cases continued to rise in the county during the lockdown”, writes The Times’ science editor Tom Whipple.

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Kent, along with London and the Home Counties, remains the epicentre of the new outbreak, but cases have been seen across the country.

Last week Health Secretary Matt Hancock told the House of Commons yesterday that almost 60 local authorities had identified a total of more than 1,000 Covid infections caused by the new variant. “And numbers are increasing rapidly,” he added.

And yesterday, the Chief Scientific Adviser Patrick Valance warned that it was likely to spread. “We know that there are cases everywhere,” he said. “It is not as though we can stop this getting into places.”

It is less clear how far the new variant has spread internationally, but isolated cases have already been detected in Australia, the Netherlands and Belgium.

How is it different?

The new variant, called B.1.1.7, is missing two pieces of genetic material found in the more common strain of the coronavirus.

Although the precise effect is unknown, one theory “is that the mutations make the virus a bit harder for your immune system to kill, so it survives a little longer in the bloodstream”, says science writer Tom Chivers on Unherd.

As a result, people with the virus would also be infectious for longer, and would therefore have more opportunity to infect others.

Boris Johnson said on Saturday that the new variant increases the R-number by 0.4, meaning that 100 people with the new strain of Covid would, on average, infect 40 more people than they would have done with the old strain.

Does the mutation make the virus more deadly?

“There is no evidence to suggest that it does, although this will need to be monitored,” says the BBC. Chief Medical Adviser Chris Whitty has said that hospitalisation and mortality rates are not significantly different in areas with the new strain.

Will the vaccines still work?

We don’t yet know for sure, but the “working assumption at the moment, from all of the scientists, is that the vaccine response should be adequate for this virus”, Whitty said on Saturday.

We can be “reasonably hopeful”, says Chivers, because the vaccines act against the virus on multiple fronts, producing B-cell immunity through specific antibodies and broader T-cell immunity.

“The new strain could have a slightly shorter period of B-cell immunity,” Chivers adds, “but it’s very unlikely that we’d lose T-cell immunity altogether”.