The UK coronavirus variant has not been identified through sequencing efforts in the United States, the US Centers for Disease Control and Prevention said in a scientific brief posted on its website Tuesday.
However, it says, only about 51,000 of 17 million US cases it has tallied have been sequenced — less than half a percent.
"Ongoing travel between the United Kingdom and the United States, as well as the high prevalence of this variant among current UK infections, increase the likelihood of importation," the agency says.
"Given the small fraction of US infections that have been sequenced, the variant could already be in the United States without having been detected."
The agency says: "CDC is monitoring the situation in the UK and communicating with the European Centre for Disease Prevention and Control. CDC and state and local health departments are continually monitoring and studying the virus spreading in the United States to quickly detect any changes."
Last month, the agency launched a "strain surveillance program”" that it expects to be "fully implemented" in January; it will include states sending at least 10 samples biweekly for analysis.
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