Highly Transmissible Delta Variant AY.4.2 Detected In At Least Eight States

A highly transmissible descendant of the Delta coronavirus variant has been detected in at least eight states. The U.K. is also monitoring a growing number of cases.

The AY.4.2 variant has turned up in labs in California, Florida, Massachusetts, Rhode Island, Maryland, Nevada, Washington State, North Carolina, and D.C. 

Experts warn that it is a faster-spreading “sub-lineage” of Delta, but there is no evidence suggesting it causes more illnesses. They say current vaccines are effective against it. 

“Right now, I think there’s not a lot that we know. But in terms of the risk that it poses to public health, the prevalence is very low in the U.S., and we don’t really anticipate that the substitutions [of AY.4.2] are going to have a significant impact on either the effectiveness of our vaccines or its susceptibility to monoclonal antibody treatments,” said Dr. Summer Galloway, executive secretary of the U.S. government’s SARS-CoV-2 Interagency Group.

However, the numbers of the new “Delta Plus” variant remain low. It’s estimated that AY.4.2 makes up about .05 percent of cases circulating the U.S. for weeks. The Centers for Disease Control and Prevention estimates that the Delta variant and its descendants make about 100 percent of cases in the country for months.

In the U.K., AY.4.2 makes up more than 11 percent of the cases of the Delta variant.