New Coronavirus Strain From UK May Already Be In US, CDC Says

The new coronavirus strain that was first detected in the United Kingdom may already be spreading across the United States, according to the Centers for Disease Control and Prevention.

On Tuesday, the CDC said the variant has yet to be found in the U.S. However, American scientists have only sequenced viruses from 51,000 of the 18.2 million cases across the nation, which means the new strain may be circulating without notice.

“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 CDC said in a statement. “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 new COVID-19 strain, which is being referred to as “B.1.1.7,” first came to the attention of researchers in December after the variant was found in many samples taken from areas in southern England. The samples were subsequently found to have been collected from patients in September.

The new strain accounts for 60% of recent cases in London and other areas in the U.K.

The new variant has been found to have 23 mutations, according to the CDC. While 23 mutations do not make COVID-19 deadlier, they could make the virus up to 70% more transmissible.

"Based on these mutations, this variant strain has been predicted to potentially be more rapidly transmissible than other circulating strains of SARS-CoV-2," the CDC said.

The new strain also has been detected in several countries outside the U.K., including Denmark, Belgium, Italy and Australia. Researchers in South Africa have also detected a similar but separate COVID-19 variant.

Many of the coronavirus cases affected by this variant involved people under the age of 60. Patients younger than 60 are often asymptomatic, according to CNN Senior Medical Correspondent Elizabeth Cohen.

“That may be why this is spreading so quickly -- or part of the reason -- is that many of these people aren't showing symptoms, so they're running around and spreading it," she said.

Some scientists, including Imperial College London virologist Wendy Barclay, also believe the new strain could potentially make children as susceptible to infection as adults.