The study finds that the UK coronavirus strain doubles every 10 days in the United States every 10 days

The mutant coronavirus strain first identified in the UK remains at low levels in the United States, but doubles its range about every 10 days, according to a study released Sunday by researchers.

The study reinforced the modeling done by the Centers for Disease Control and Prevention, which predicted last month that the most contagious variant could be the dominant strain in the United States in March.

The United States still has time to take steps to slow the new strain of the virus, the researchers wrote, but warned that without “immediate and decisive public health action” the variant “is likely to have devastating consequences on mortality and morbidity.” COVID-19 USA in a few months. “

The research, funded in part by the CDC and the National Institutes of Health and the Canadian Institutes of Health Research, was published on medRxiv, a prepress server, and has not yet been peer-reviewed.

The new coronavirus strain, also known as B.1.1.7, spread rapidly throughout the United Kingdom and has become the dominant strain in this country, which by some measures is the most affected in Europe.

Health officials have said existing vaccines are likely to work against new strains, although their effectiveness may be reduced somewhat.

The study found that there are “relatively low” amounts of B.1.1.7. in the United States at this time, but which, given its rapid expansion, is “almost certainly destined to become the dominant SARS-CoV-2 lineage in March 2021.”

The new strain accounted for 3.6% of coronavirus cases in the U.S. during the last week of January, according to the study.

The researchers noted that monitoring the national spread of the strain is complicated by the lack of a national genomics surveillance program such as those found in the United Kingdom, Denmark and other countries.

They wrote that they had “relatively robust” estimates of California and Florida, but that data outside of those states was limited.

The growth rate of the virus diverged in the two states, with B.1.1.7. it seems to be spreading a little slower in California. The study authors wrote that the strain doubled every 12.2 days in California, 9.1 days in Florida, and 9.8 days nationwide.

The study supports the conclusion that the new strain is already spreading through a “significant community transmission”.

The authors suggest that the virus was introduced into the country through international travel and spread through domestic travel as millions of Americans crossed the country around the Thanksgiving, Christmas, and New Year holidays. autumn and winter.

The authors also found that the variant was growing a little slower than in European countries, which they said requires further research, but may be the result of current data shortages or other factors, including the “competition from other more transmissible variants”. .

Other strains of coronavirus of concern have been detected in South Africa and elsewhere.

The researchers warned that their findings “reinforce the need” for robust surveillance in the U.S. of possible new and emerging coronavirus variants.

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

“The most established surveillance programs in other countries have provided important warnings about worrying variants that may affect the United States, with B.1.1.7 representing only one variant that demonstrates exponential growth capacity,” they added.

“Only with coherent and impartial sequencing at scale that includes all geographic and demographic populations, including the often underrepresented, along with continued international scientific collaborations and open data sharing, will we be able to accurately assess and track emerging new variants. during the COVID-19 pandemic, “the researchers wrote.