A more contagious variant of the coronavirus first found in Britain is spreading rapidly in the United States, doubling roughly every 10 days, according to a new study.

Analyzing half a million coronavirus tests and hundreds of genomes, a team of researchers predicted that in a month this variant could become predominant in the United States, potentially bringing a surge of new cases and increased risk of death.

The new research offers the first nationwide look at the history of the variant, known as B.1.1.7, since it arrived in the United States in late 2020. Last month, the Centers for Disease Control and Prevention warned that B.1.1.7 could become predominant by March if it behaved the way it did in Britain. The new study confirms that projected path…

“There could indeed be a very serious situation developing in a matter of months or weeks,” said Nicholas Davies, an epidemiologist at the London School of Hygiene and Tropical Medicine who was not involved in the study. “These may be early signals warranting urgent investigation by public health authorities.”