MONDAY, Feb. 8, 2021 (HealthDay News) -- The highly contagious coronavirus variant that drove Britain into lockdown in December is now spreading quickly across the United States, a new study shows.
What has been dubbed the B.1.1.7 variant is doubling its prevalence every nine days in this country, according to a report posted on the preprint server MedRxiv on Sunday and not yet peer-reviewed or published in a journal. The findings, from a large collaboration of scientists, buttresses a forecast issued last month by the U.S. Centers for Disease Control and Prevention that showed the variant becoming dominant in this country by late March.
The researchers scrutinized genomic analyses of the virus samples from 10 states, including from 212 infections involving the variant, and concluded that the variant has been 35 to 45 percent more transmissible than other variants in the United States.
"It is here, it's got its hooks deep into this country, and it's on its way to very quickly becoming the dominant lineage," study co-author Michael Worobey, an evolutionary biologist at the University of Arizona, told the Washington Post.
"Those models are very sensitive to assumptions about how many people the average infected person passes the virus to. If those assumptions are off by just a bit, or if we let our guard down and relax mitigation measures, I believe we could well see a dangerous upward surge of cases as B.1.1.7 comes to dominate the U.S. epidemic in March," Worobey added.
"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 authors of the new report said.
In the study, Florida stands out as the state with the highest estimated prevalence of the variant. The new report estimated the doubling time of B.1.1.7 prevalence in positive test results at just over nine days.
Florida leads the nation in reported B.1.1.7 cases, with 201 as of Monday, followed by much more populous California with 145, according to the CDC. A total of 690 cases have been reported in 33 states, according to the CDC.
The new study only looked at data through the end of January, but the percentage of B.1.1.7 infections in Florida may have risen from a little less than 5 percent to approximately 10 percent in just the past week in Florida, study co-author Kristian Andersen, an immunologist at Scripps Research Institute, told the Post Sunday.
Mary Jo Trepka, an epidemiologist at Florida International University, told the newspaper she is not surprised by the spread of the variant in Florida, because the state has not been strict about mask mandates or other restrictions, while at the same time it is a hub for international travel.
"The message is that we have to work harder to prevent transmission of all these cases of COVID," she said. "If we don't, we'll potentially see more variants. We need to get everybody vaccinated and we need to do a much better job at preventing transmission."
The variant first appeared in genomic surveys in the United Kingdom in September, but did not get tagged as a "variant of concern" until early December when its rapid spread stunned scientists and prompted lockdowns in southern England.
"What concerns me is the exponential growth in the early stages doesn't look very fast," Andrew Noymer, an epidemiologist at the University of California, Irvine, who was not part of the new study, told the Post. "It kind of putzes along — and then goes boom."