Kent variant of coronavirus up to twice as deadly, study suggests

‘Coupled with its ability to spread rapidly, this makes B117 a threat that should be taken seriously,’ says epidemiologist

Tom Batchelor
Wednesday 10 March 2021 14:04
Coronavirus in numbers

The more infectious Kent variant of coronavirus may be up to twice as deadly compared with previously circulating forms of Covid-19, a new study suggests.

Epidemiologists from the universities of Exeter and Bristol found the B117 variant, which took hold in southeast England last year before spreading around the world, is between 30 per cent and 100 per cent more deadly.

Robert Challen, lead author of the study from the University of Exeter, concluded that the Kent variant does “raise the risk” of dying from the disease.

“Coupled with its ability to spread rapidly, this makes B117 a threat that should be taken seriously,” he said.

Analysing death rates among people infected with the new variant, researchers found it led to 227 deaths in a sample of 54,906 patients – compared with 141 among the same number of closely matched patients who had the variant circulating earlier in the pandemic.

Research has already shown that the B117 variant is more transmissible and is thought to have contributed towards the rapid increase in cases before new lockdown rules were introduced across the UK.

According to the study, published in the British Medical Journal, the higher transmissibility of the Kent variant meant that more people who would previously have been considered low risk were admitted to hospital.

“The variant of concern, in addition to being more transmissible, seems to be more lethal,” the study said.

“This development, borne out in epidemiological analyses, implies that the rate of patients with serious infection requiring hospital attention will increase.”

Leon Danon, a senior author of the study from the University of Bristol, said: “We focused our analysis on cases that occurred between November 2020 and January 2021, when both the old variants and the new variant were present in the UK.

”This meant we were able to maximise the number of 'matches' and reduce the impact of other biases. Subsequent analyses have confirmed our results.

“Sars-CoV-2 appears able to mutate quickly, and there is a real concern that other variants will arise with resistance to rapidly rolled out vaccines.

”Monitoring for new variants as they arise, measuring their characteristics and acting appropriately needs to be a key part of the public health response in the future.“

Ellen Brooks-Pollock, from the University of Bristol, said: ”It was fortunate the mutation happened in a part of the genome covered by routine testing. Future mutations could arise and spread unchecked.”

In January a paper from the New And Emerging Respiratory Virus Threats Advisory Group (Nervtag) said there was a “realistic possibility” that the variant was associated with an increased risk of death. However, scientists have also warned there was a lot of uncertainty around the data.

Mutations of the virus have raised concerns about whether vaccines would be effective against new strains, including the now-dominant Kent strain.

But research suggests the Pfizer jab is just as effective against the Kent variant of coronavirus, while other data indicates the Oxford/AstraZeneca jab has a similar efficacy against it.

Dr Michael Head, a senior research fellow in global health at the University of Southampton, said: “This new study underpins findings previously considered by Nervtag, that the B117 variant of concern does appear to have a higher mortality rate, compared with the previously-circulating variant. There is already good evidence that this variant is more transmissible.

“This will have contributed to the rises in cases and deaths over the last few months, but it is important to note that when the November lockdown ended, daily figures were then heading in the wrong direction anyway – the variant exacerbated the increases in new daily cases and deaths, but did not cause them.

“This also illustrates the importance of keeping case numbers suppressed, and the futility of those who called for the virus to be able to spread relatively freely, such as supporters of the Great Barrington Declaration.

“The more Covid-19 there is, the more chance there is of a new variant of concern emerging. This includes the possibilities of variants that can have an impact on the vaccine roll-out.

“Thus, the recent calls for the UK to open up faster than the plans in the roadmap would be a reckless gamble, and we simply must proceed with caution in the short-term to give ourselves the better prospects in the long-term.”

Additional reporting by PA

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