The faster-spreading coronavirus variant first detected in the United Kingdom is on its way to becoming the dominant form of the virus in the United States, WebMD reported on Friday.

A new study found that the B.1.1.7 variant is being detected in a growing proportion of SARS-CoV-2 samples and is 40% to 50% more transmissible than versions of the virus that were previously dominant.

Together with previous research showing that the B.1.1.7 variant may be about 50% more deadly, the new findings suggest that the U.S. could have more coronavirus infections and deaths than previously expected, according to the authors of the study, published March 31 in the journal Cell.

“B.1.1.7 rapidly became the dominant SARS-CoV-2 variant in the U.K. and other countries after its emergence late last year, and the U.S. is now on a similar trajectory,” said study co-senior author Kristian Andersen. He’s director of Infectious Disease Genomics at the Scripps Research Translational Research Institute in La Jolla, Calif.

“We need immediate and decisive action to minimize COVID-19 morbidity and mortality,” he added in a Scripps news release.

“B.1.1.7 has a doubling rate of a little over a week and an increased transmission rate of 40%-50%, which means it could have a meaningful impact on public health,” said study co-senior author William Lee, vice president of science at Helix, which provides PCR-based coronavirus testing to organizations across the United States.

“It is critical that we continue to monitor the spread of this and other emerging variants, but our current level of surveillance is inadequate and lags behind that of other countries,” Lee said in the release. “We need a more comprehensive national SARS-CoV-2 genomics surveillance program to address this.”

There is no evidence yet that the B.1.1.7 variant is resistant to coronavirus vaccines, but public health officials fear its higher rate of spread will significantly worsen the pandemic before it can be halted by vaccines.

Last year, the B.1.1.7 variant emerged in southern England and has since become the dominant variant there. In December, California confirmed the first evidence of the variant in the United States.

The researchers found that the B.1.1.7 variant has been introduced to the U.S. several times since at least late November 2020, especially in California and during periods when there was increased travel, including Thanksgiving week.