That estimate is higher than those from previous studies into the variant of the Chinese Communist Party (CCP) virus, commonly known as the novel coronavirus.
In a sample of over 50,000 patients, the new variant—sometimes called the Kent variant—led to 227 deaths, compared to 141 in a matched sample of people who had the previous strains.
“The highly infectious variant of COVID-19 discovered in Kent, which swept across the UK last year before spreading worldwide, is between 30 and 100 percent more deadly than previous strains, new analysis has shown,” reads a statement from the study authors.
The lead author of the study, Robert Challen from the University of Exeter, said, “In the community, death from COVID-19 is still a rare event, but the B.117 variant raises the risk. Coupled with its ability to spread rapidly this makes B.117 a threat that should be taken seriously.”
The study, by the universities of Bristol and Exeter, underpins previous findings by scientific advisers to the UK government.
“The precise mechanisms responsible for increased mortality associated with the variant remain uncertain,” said Lawrence Young, a virologist at the University of Warwick. “But could be related to higher levels of virus replication as well as increased transmissibility. The UK virus variant (B.1.1.7) is fuelling the recent surge in infections across Europe with over [a] million new cases reported last week, an increase of 9% from the previous week.”
However, Julian Tang, a clinical virologist at the University of Leicester, is not convinced by the latest study.
“Clinical teams know that the coldest winter temperatures occurring in Jan/Feb can exacerbate all the comorbidities that predispose to more severe outcomes of COVID-19—like chronic heart, lung, renal, neurological diseases—including diabetes, hypertension (stressing the heart),” he said in a statement.
“So without the careful matching of comorbidities in the VOC [variant of concern] and non-VOC arms, these differential clinical severity model outcomes are still questionable.
“We really need to revisit this in Spring to account for the cold weather factor—and there are also other seasonal variables related to shorter daylight hours, such as melatonin levels that may impact differentially on VOC vs. non-VOC clinical outcomes—related to host immune responses.”
The UK variant has long been thought to spread faster, but whether it is more deadly has been less clear.
The first evidence suggesting it could be more deadly was first announced by Prime Minister Boris Johnson in January.
In February, another study suggested it could cause 30–70 percent more deaths.
The new variant was first identified in the UK towards the end of last year and became the predominant strain during the pandemic wave in the winter.
Infection rates of the virus peaked in the UK at the start of January, according to official data, and are now at their lowest since October.