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Washington (AFP)
A variant of the coronavirus first identified in Britain is spreading rapidly in the United States, threatening to cause an increase in new cases, doubling roughly every 10 days, according to a new study.
The document was posted online Sunday and has yet to be peer-reviewed, but it offers the most comprehensive view of the rise of B.1.1.7 in the country hardest hit by the pandemic.
A team of scientists led by researchers from the Scripps Research Institute analyzed half a million test samples collected across the country since last summer.
Rather than individually sequencing them all, they were able to identify one particular anomaly that was a “trusted proxy” for B.1.1.7.
They also analyzed the complete genetic sequence, a process that requires more time, for 212 samples.
They found that the variant was introduced at various points in the US in November 2020, and while it currently has a low overall frequency, it will become the dominant form of the virus in March.
The team added that the transmission rate was at least 35-45 percent higher than the most common variants, with its prevalence doubling every week and a half.
Britain saw devastating waves from Covid after B.1.1.7 became dominant there, and the variant has been observed in many European countries, including Portugal and Ireland.
“B.1.1.7 is much more contagious, so it can quickly overwhelm a nation,” Ashish Jha, dean of the School of Public Health at Brown University, tweeted in response to the document.
Ireland had managed to get its outbreak under control in late 2020, but in January B.1.1.7 it set off an exponential wave from which it is now recovering.
The United States is the worst-affected country in the world, with more than 27 million confirmed cases and 460,000 deaths, but its latest wave peaked around January 8 and infections have been declining since.
There are fears that B.1.1.7 could trigger a new spike, and it is spreading particularly fast in Florida, according to the study.
The study authors asked the United States to develop its Covid genomic surveillance system.
Current vaccines remain effective against the variant, while the use of masks dramatically reduces transmission.
© 2021 AFP
