LONDON—British officials warned Friday that a coronavirus variant first identified in the U.K. might be more lethal as well as more transmissible than previous versions of the pathogen.
The conclusions of scientists advising the British government are still highly uncertain. But British Prime Minister Boris Johnson said in a televised address that the variant—which has caused Covid-19 infections across the U.K. to spike and is spreading rapidly in the U.S.—could result in higher death rates.
U.S. federal health authorities have said it is likely to become the dominant variant in the U.S. by March.
“We have been informed today that, in addition to spreading more quickly, it also now appears that there is some evidence that the new variant—the variant that was first identified in London and the South East—may be associated with a higher degree of mortality,” said Mr. Johnson.
The tentative conclusions come as British hospitals cope with more Covid-19 patients than at any time during the pandemic. The Covid-19 death toll in the U.K. is expected to pass 100,000 in the coming week.