U.K. COVID-19 variant doubling every 10 days in the U.S.: Study


The SARS-CoV-2 variant first detected in the United Kingdom is rapidly becoming the dominant strain in several countries and is doubling every 10 days in the United States, according to new data.

The findings by Nicole L. Washington, PhD, associate director of research at the genomics company Helix, and colleagues were posted Feb. 7, 2021, on the preprint server medRxiv. The paper has not been peer-reviewed in a scientific journal.

The researchers also found that the transmission rate in the United States of the variant, labeled B.1.1.7, is 30%-40% higher than that of more common lineages.

While clinical outcomes initially were thought to be similar to those of other SARS-CoV-2 variants, early reports suggest that infection with the B.1.1.7 variant may increase death risk by about 30%.

A coauthor of the current study, Kristian Andersen, PhD, told the New York Times , “Nothing in this paper is surprising, but people need to see it.”

Dr. Andersen, a virologist at the Scripps Research Institute in La Jolla, Calif., added that “we should probably prepare for this being the predominant lineage in most places in the United States by March.”

The study of the B.1.1.7 variant adds support for the Centers for Disease Control and Prevention prediction in January that it would dominate by March.

“Our study shows that the U.S. is on a similar trajectory as other countries where B.1.1.7 rapidly became the dominant SARS-CoV-2 variant, requiring immediate and decisive action to minimize COVID-19 morbidity and mortality,” the researchers wrote.

The authors pointed out that the B.1.1.7 variant became the dominant SARS-CoV-2 strain in the United Kingdom within a couple of months of its detection.

“Since then, the variant has been increasingly observed across many European countries, including Portugal and Ireland, which, like the U.K., observed devastating waves of COVID-19 after B.1.1.7 became dominant,” the authors wrote.

“Category 5” storm

The B.1.1.7 variant has likely been spreading between U.S. states since at least December, they wrote.

This news organization reported on Jan. 15 that, as of Jan. 13, the B.1.1.7 variant was seen in 76 cases across 12 U.S. states, according to an early release of the CDC’s Morbidity and Mortality Weekly Report.

As of Feb. 7, there were 690 cases of the B.1.1.7 variant in the US in 33 states, according to the CDC.

Dr. Washington and colleagues examined more than 500,000 coronavirus test samples from cases across the United States that were tested at San Mateo, Calif.–based Helix facilities since July.

In the study, they found inconsistent prevalence of the variant across states. By the last week in January, the researchers estimated the proportion of B.1.1.7 in the U.S. population to be about 2.1% of all COVID-19 cases, though they found it made up about 2% of all COVID-19 cases in California and about 4.5% of cases in Florida. The authors acknowledged that their data is less robust outside of those two states.

Though that seems a relatively low frequency, “our estimates show that its growth rate is at least 35%-45% increased and doubling every week and a half,” the authors wrote.

“Because laboratories in the U.S. are only sequencing a small subset of SARS-CoV-2 samples, the true sequence diversity of SARS-CoV-2 in this country is still unknown,” they noted.

Michael Osterholm, PhD, MPH, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, Minneapolis, said last week that the United States is facing a “Category 5” storm with the spread of the B.1.1.7 variant as well as the variants first identified in South Africa and Brazil.

“We are going to see something like we have not seen yet in this country,” Dr. Osterholm said recently on NBC’s Meet the Press.

Lead author Nicole L. Washington and many of the coauthors are employees of Helix. Other coauthors are employees of Illumina. Three coauthors own stock in ILMN. The work was funded by Illumina, Helix, the Innovative Genomics Institute, and the New Frontiers in Research Fund provided by the Canadian Institutes of Health Research.

A version of this article first appeared on Medscape.com.

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