An emerging COVID-19 strain, XEC, has been detected in 12 U.S. states and at least 15 countries, according to Scripps Research's Outbreak.info.
The variant was first reported in late June, and as of Sept. 3, 95 sequences of the XEC lineage have been detected, according to Scripps.
Experts told USA Today they expect XEC and another variant, MV.1, to become dominant strains. Both are already in the U.S. but are not on the CDC's COVID-19 variant proportions tracker as of Sept. 17.
The 12 states are Arizona, California, Florida, Maryland, New Jersey, New York, North Carolina, Pennsylvania, South Dakota, Texas, Virginia and Washington.
The CDC has not reported whether XEC and MV.1 are more severe than other variants, but scientists told the Los Angeles Times that XEC could eventually surpass KP.3.1.1, which, the CDC reports, accounts for 52.7% of infections.
XEC "is just getting started now around the world and here," Eric Topol, MD, PhD, director of the Scripps Research Institute in La Jolla, Calif., told the LA Times. "And that's going to take many weeks, a couple months, before it really takes hold and starts to cause a wave."
Peter Chin-Hong, MD, told the San Francisco Chronicle that XEC likely won't cause a spike in hospitalizations and deaths. He predicts the variant will infect more people, though, because of its transmissibility.
"With these new transmissible variants, they will likely infect people who were otherwise not going to get infected," said Dr. Chin-Hong, an infectious disease specialist at UCSF in San Francisco.