New Coronavirus Strain Could Be Present in the U.S., CDC Says

(Bloomberg) -- The new variant of the coronavirus that’s become prevalent in the U.K. in recent weeks could be in the U.S. undetected, according to the Centers for Disease Control and Prevention.

No cases of the new strain have yet been found in the U.S., the CDC said on its website Tuesday. But the agency said viruses have only been sequenced from about 51,000 of the 17 million U.S. cases.

Travel between the countries and the prevalence of the strain in the U.K. boost the chance it’s already infecting Americans, the CDC said. Since November, the strain has accounted for roughly 60% of new coronavirus cases in London, according to the CDC.

Scientists are working to determine whether the strain is more transmissible, the agency said, and if the currently authorized vaccines from Moderna Inc. and Pfizer Inc. and BioNTech SE will protect people against it.

Concern that the new variant could hasten transmission and increase the burden faced by health-care systems led the U.K. to tighten its lockdown measures. Many countries in Europe have also closed their borders to travelers arriving from the U.K.

The U.S., however, remains open to travelers arriving from Britain.

The potential that a new strain could evade the vaccines caused shares of Pfizer, Moderna and other drugmakers to decline on Tuesday, and worry that new quarantines to contain the fresh mutation could slow down the global recovery pressured stock markets more broadly.

It remains unclear however whether physical characteristics of the new variant have led to that prevalence, or if it is a byproduct of people’s interactions in London.

The coronavirus mutates regularly, the CDC said, acquiring roughly one new mutation in its genome every two weeks.

The agency said that the possible consequences of a change in the virus’s structure include the ability to spread more quickly, to cause either milder or more severe disease, to elude screening tests, to be less likely to be treated with existing drugs and to evade vaccines.

The latter is the most troubling possibility, the agency said.

In an interview with Bloomberg News on Monday, BioNTech Chief Executive Officer Ugur Sahin said he expects its shot would be effective against the strain, despite mutations in the spike protein targeted by vaccines. Moncef Slaoui, the head of the U.S. vaccine program Operation Warp Speed, also said Monday he expected the current vaccines would still offer protection.

©2020 Bloomberg L.P.