New coronavirus strain behind a fifth of cases in Norfolk, data shows | Coronavirus

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A new strain of coronavirus is behind a fifth of all cases in Norfolk, fresh data has suggested, as a leading scientist called for the Covid vaccination programme to be ramped up to contain its spread.

The variant was picked up by Public Health England surveillance in London and Kent but has spread to other regions, accounting for 20% of viruses sequenced in Norfolk – mostly around Norwich – 10% in Essex, and 3% in Suffolk. Other cases have been reported in Scotland and Wales. The rate in London varies between boroughs.

Urgent studies are under way at Porton Down and other specialist laboratories to determine whether the strain spreads more easily or partially evades the immune system, with preliminary research suggesting there are reasons to be concerned.

Matt Hancock, the health secretary, announced the discovery of the variant on Monday, saying it may be driving the rise in infections in London and the south-east, before moving the areas into tier 3 Covid restrictions.

While there is no evidence it causes more serious disease, or that Covid vaccines will fail to protect against it, scientists suspect the variant may spread faster, making it harder to contain, particularly amid relaxed Christmas rules.

Ravi Gupta, a professor of clinical microbiology at Cambridge University, who is working on the strain, urged people to make extra efforts to prevent the spread of the virus and called for the vaccination programme to be accelerated.

“The way to stop this is to stop it mutating any further. The more it transmits, the more it will have the potential to gain other abilities, so the most sensible thing is to ramp up vaccination and shut down,” he said.

Gupta said there may be a case for focusing immediate vaccinations on the south-east and other areas where the multi-mutant variant has taken off. “One thing that should be modelled or discussed is should we vaccinate the south-east, though the mutant has spread beyond there,” he said. More than 1,000 cases have been identified in 60 local authority areas, predominantly in the south and east.

The new variant, named VUI – 202012/01, has seven mutations in the spike protein that studs the surface of the virus. The spike protein is the key the virus uses to unlock human cells and infect them. It is also the target for many antibodies. Mutations to the spike protein often have little impact but they can potentially change the virus’s infectivity or make it less susceptible to antibodies unleashed by the immune system.

A key mutation in the new strain, known as delta 69/70, has cropped up in thousands of coronavirus samples around the world. Scientists are investigating whether the mutation helps the virus, perhaps by evading antibodies or by boosting its ability to infect human cells. Preliminary tests at Gupta’s lab suggest the mutation might increase the virus’s infectivity, but more extensive work is needed to confirm the finding.

One reason delta 69/70 is causing concern is that other versions of the coronavirus already in circulation appear to spread faster when they acquire the mutation.

From March, versions of Covid-19 carrying a mutation called N439K rose fairly steadily, but soared in August when they evolved the delta 69/70 mutation too, according to Gupta’s research, which has not yet been peer reviewed. Another lineage of the coronavirus containing a mutation called N501Y took off in September when it acquired the delta 69/70 mutation. The multi-mutant variant spreading in southern England is a subgroup of this latter lineage.

In a striking example of the virus’s ability to evolve, the same delta 69/70 mutation suddenly appeared in coronavirus samples collected from a Cambridge patient with a weakened immune system. The patient was being treated with convalescent plasma – blood plasma rich in antibodies from recovered Covid patients.

During the treatment, which lasted several months, the virus evolved the delta 69/70 mutation and became partially resistant to the antibodies in the plasma. The patient did not survive the infection.

While the mutations are a concern, Gupta believes the vaccines being rolled out will still protect against the variant. Vaccines stimulate the body to produce a broad range of different antibodies that attack the virus from different angles and it is unlikely that the mutations would confer complete resistance to all of them.

“I don’t think the vaccine will be compromised, but that situation may change depending on what we do,” he said.

Hafta Ichi
Source: The Guardian
Keyword: New coronavirus strain behind a fifth of cases in Norfolk, data shows | Coronavirus

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