The United Kingdom variant of COVID-19 is more deadly than other coronavirus strains, according to a study in the British Medical Journal published Wednesday.
Researchers at the University of Exeter and the University of Bristol said that variant B.1.1.7 was associated with a “significantly higher mortality” rate among adults compared to previously circulating strains.
The universities said in a statement the U.K. strain was between 30 percent and 100 percent more deadly than other variants.
The study found that of 54,609 COVID-19 patients who tested positive for the mutated strain, 227 died within 28 days. By comparison, 141 who tested positive for other strains died out of the same number of patients.
“In the community, death from COVID-19 is still a rare event, but the B.1.1.7 variant raises the risk,” Robert Challen, lead author of the study from the University of Exeter, said in a statement. “Coupled with its ability to spread rapidly this makes B.1.1.7 a threat that should be taken seriously.”
The first case of B.1.1.7 was found in the U.K. in September, Reuters noted. It has 23 mutations in its genetic code, some of which make the strain easier to spread.
According to the Centers for Disease Control and Prevention, there are 3,283 cases of the B.1.1.7 variant reported across 49 jurisdictions in the U.S.
Several vaccine makers — including Pfizer-BioNTech and Moderna — have said their vaccines are effective against the U.K. variant.