LONDON – British government scientists are increasingly discovering that the coronavirus variant first detected in Britain is more deadly than the original virus, a devastating trend that highlights the serious risks of this new phase of the pandemic.
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Taking a patient out of the Royal London Hospital in London this month.
Scientists said last month that there was a “realistic possibility” that the variant was more lethal. Now, they state in a new document that it is “likely” that the variant is linked to an increased risk of hospitalization and death.
The British government has not publicly announced the updated findings, which are based on almost twice as many studies as its previous assessment and include more deaths from Covid-19 cases caused by the new variant, known as B.1.1.7. The document was posted on a government website on Friday and said it had been considered at a meeting of government advisers the previous day.
The variant is known to be in 82 countries, including the United States. American scientists recently estimated that it was spreading rapidly there, doubling approximately every 10 days, and said it could be the dominant version of the virus in the United States in March.
“Calculating when we can lift the restrictions has to be influenced by that,” said Simon Clarke, associate professor of cell microbiology at the University of Reading, about the new findings. “This provides extra evidence that this variant is more lethal than the one we dealt with last time.”
Most cases of Covid-19, even those caused by the new variant, are not fatal. And government scientists were relying on studies that examined a small proportion of deaths in general, making it difficult to pinpoint how much increased risk may be associated with the new variant.
A number of unavoidable limitations on the data also remained, including the fact that it was difficult to control whether cases of the variant were occurring in nursing homes. Government scientists said the most powerful studies need more data on deaths before they can examine the effect of the variant more conclusively.
But the most solid studies that government scientists have trusted estimate that the variant may be 30 to 70 percent more lethal than the original virus.
And the additional evidence, they wrote, allowed “to increase confidence in the association” of the new variant “with the increasing severity of the disease”.
The variant is believed to be 30 to 50 percent more transmissible than the original virus, although some scientists now believe it to be even more contagious than that. The first sample was collected in southeastern England in September and quickly became the dominant version of the virus in Britain. It is now responsible for more than 90 percent of cases in many parts of the country.
As it spread, hospitals became overwhelmed with the pace of new infections, with doctors and nurses treating almost twice as many hospitalized patients as they did during last year’s peak. A strict block since then has drastically reduced the number of new coronavirus cases in Britain.
As an example of the growing evidence of the variant’s lethality, government scientists cited a study by the London School of Hygiene and Tropical Medicine. In January, that study examined the deaths of 2,583 people, 384 of whom are believed to have had cases of Covid-19 caused by the new variant. The research estimated that people infected with the new variant had a 35% higher risk of dying.
© Andrew Testa for The New York Times
An empty street in London last month.
An updated study by the same group was based on 3,382 deaths, 1,722 of which are believed to be of the new variant. This study suggested that the variant may be associated with a 71% higher risk of dying.
Professor Clarke said the new findings justified the British government’s decision to raise an alarm over the variant in December and publish evidence last month that it was potentially more lethal. Some outside scientists initially rejected the warnings.
“They did not retain the data,” said Professor Clarke. “They were very frank about how uncertain things were.”
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