LONDON – UK government scientists are increasingly realizing that the variant of coronavirus, first discovered in the UK, carries a higher risk of death than other versions of the virus. This is a devastating trend that highlights the serious risks and significant uncertainties of this new phase of the pandemic.
The scientists said last month that there is a “realistic possibility” that the variant is not only more contagious than others, but also more deadly. A new document now states that it is “likely” that the variant is associated with an increased risk of hospitalization and death.
The UK government has not made the updated results public. These are based on about twice as many studies as their earlier assessment and include more deaths due to Covid-19 cases caused by the new variant B.1.1.7. The document was posted on a government website on Friday.
The reasons for an increased death rate are not entirely clear. Some evidence suggests that people infected with the variant may have higher viral loads, which not only makes the virus more contagious, but could potentially undermine the effectiveness of certain treatments.
But scientists are also trying to understand to what extent the increased risk of death is due to the tendency of the variant to spread very easily in facilities such as nursing homes, where people are already at risk.
Regardless of the statement, UK government scientific advisers said Saturday the new evidence revealed the dangers of countries easing restrictions while the variant kicks in.
The variant has spread to at least 82 countries and, according to estimates by scientists, is 35 to 45 percent easier to transmit than other variants in the United States. American officials have suggested that the variant could be the dominant source of infection there by March.
“The bigger picture shows an increase in the risk of hospitalization and death by around 40 to 60 percent,” said Neil Ferguson, epidemiologist and scientific advisor to the UK government, in an interview on Saturday. Regarding the severe socialization restrictions that are in place across the UK, he said, “It reinforces existing policies.”
Most Covid-19 cases, including those caused by the new variant, are not fatal. And government scientists relied on studies that looked at a small fraction of the total deaths.
Scientists also struggled to explain the presence of underlying diseases in people infected with the new variant and to determine if the cases came from nursing homes.
Apr. 13, 2021, 6:10 p.m. ET
For the most part, they limited themselves to examining people who had tested positive for the virus at community test sites rather than hospitals. One quirk of hospital testing means that many cannot detect an altered gene that is often used as a proxy for the variant.
Overall, the assessment of the government scientists indicated that the variant “probably” is associated with a higher risk of death, with only 55 to 75 percent trusting the findings.
“I think these results may be real, although there are still some caveats and we need to understand what is causing them,” said Muge Cevik, an infectious disease expert at the University of St. Andrews in Scotland and a scientific advisor to the UK government.
She added that “there are other explanations for this increased severity,” including that the variant “may be disproportionately transmitted in environments with frail people such as nursing homes” because it is more transmissible.
The main danger of the new variant remains its tendency to spread: It is believed that it is 30 to 50 percent more transmissible, although some scientists estimate the number higher.
It has been the dominant source of infection in the UK since the first sample of the variant was collected in south east England in September. It now accounts for more than 90 percent of cases in many parts of the country.
A strict lockdown recently reduced the number of new cases, but only after UK hospitals were overwhelmed. A loosening of the blockage could lead to a sharp increase in the cases caused by the variant.
Around 117,000 people have died from the coronavirus in the UK, half of them since the end of November when the variant spread.
“This was pretty disastrous in terms of mortality,” said epidemiologist Dr. Ferguson. “And that is due to both the increased transferability and the increased lethality.”
A recent study by the London School of Hygiene & Tropical Medicine, on which government scientists relied, provided rough estimates of the effects of the variant. It looked at 3,382 deaths, including 1,722 in those infected with the variant, and estimated that the risk of death in the cases caused by the variant was 58 percent higher.
For example, for men aged 55 to 69, the overall risk of death increased from 0.6 percent to 0.9 percent. For women in this age group, the general risk of death increased from 0.2 percent to 0.3 percent.
“It has to affect the calculation of when we can lift restrictions,” said Simon Clarke, Associate Professor of Cell Microbiology at the University of Reading, of the new report. “It provides additional evidence that this variant is more deadly than the one we looked at last time.”
He added that the results confirmed the UK government’s decision to raise an alarm about the variant in December and then release evidence last month that it was potentially more deadly. Some outside scientists initially rejected the warnings.
“You didn’t withhold the data,” said Professor Clarke. “They were very open about how insecure things were.”