SARS-CoV-2 Variant Not Yet Detected in U.S.

By Kelly Young

Edited by David G. Fairchild, MD, MPH

A potentially more transmissible variant of SARS-CoV-2 that has become a common strain in parts of the U.K. has not been found in the U.S. yet, the CDC reported on Tuesday.

However, only about 51,000 viral samples have been sequenced in the U.S. "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 noted in a scientific brief.

In a televised interview on Tuesday, Dr. Anthony Fauci of the National Institute of Allergy and Infectious Diseases said, "When you have this amount of spread within a place like the U.K., you really need to assume that it's here already. ... It certainly is not the dominant strain but I would certainly not be surprised at all if it is already here."

The World Health Organization said the variant has been found in Australia, Denmark, Iceland, Italy, and the Netherlands. So far, this variant does not appear to cause more severe disease than other variants.

One of the variant's mutations is the N501Y mutation in the receptor binding domain. Studies of other variants with N501Y have found that they may form a tighter bond to the human angiotensin-converting enzyme (ACE2) receptor. It is unknown whether this would translate into clinical or epidemiological differences. South Africa has also reported a SARS-CoV-2 strain with the N501Y mutation, but theirs appears to have emerged independently from the one in the U.K.

Pfizer, BioNTech, and Moderna are working to determine if their vaccines will be effective against this variant, CNN reports. The vaccines have been protective against other variants of the coronavirus.