New XEC COVID Variant Identified in Some States—What to Know About Symptoms, Transmission

American infectious disease experts are now tracking a new COVID variant called XEC, which has made waves in Europe and is already spreading in the U.S.

The new variant is making headlines, as many experts speculate it could become the next predominant variant in the U.S. over the coming months.

Eric Topol, MD, executive vice president of Scripps Research, wrote on X that XEC “appears to be the most likely one to get legs next.”

The variant spread rapidly in Germany, Denmark, and the Netherlands over the summer, and there have now been cases of XEC reported in the U.S., Thomas Russo, MD, professor and chief of infectious disease at the University at Buffalo Jacobs School of Medicine and Biomedical Sciences, told Health.

However, XEC has not yet been featured in the variant surveillance data from the Centers for Disease Control and Prevention (CDC), which could be because the U.S. hasn’t seen enough cases of it yet.

“If it’s [responsible for] less than 1% [of cases], it doesn’t make the CDC surveillance chart,” Russo explained.

Even though infectious disease experts are preemptively warning people about XEC, in general, concern is still relatively low.

There’s a good chance that XEC is “quite contagious,” William Schaffner, MD, professor of medicine in the division of infectious diseases at Vanderbilt University Medical Center, told Health. But, he explained, “just because it’s new, doesn’t mean it creates any more worries than our current variants.”

Here’s what experts want you need to know about the XEC variant—including how it compares to existing variants and what to do to stay safe this fall and winter.

The Status of XEC in the U.S. Right Now

The XEC variant seems to be “more of the same,” said Schaffner. However, the possibility of its rise in the U.S. is being monitored.

According to CDC data from mid-September, KP.3.1.1 was the most dominant variant, followed by KP.2.3 and LB.1. But XEC had been reported in a handful of states—including South Dakota, Washington, Maryland, and California—as of the beginning of September.

XEC is yet another Omicron variant—more specifically, it’s related to KP.3.3, which itself is a descendant of the “FLiRT” variants that fueled a spike in cases over the summer.

“We had a considerable increase [in COVID cases] this summer,” Schaffner said. “The increase has been a bit higher, lasted a bit longer” than anticipated.

Coming off of this summer surge, it’s unclear how XEC might shape the upcoming respiratory virus season in the U.S. Though the variant spread rapidly in some European countries, experts said it will take time to sort out whether XEC is really more infectious than these previous strains.

But experts do think that the new COVID vaccines—now available in the U.S.—will offer protection against the XEC variant. “Very early laboratory” reports suggest that this is the case since XEC is in the Omicron family, said Schaffner.

The protection may be slightly less effective against the XEC variant as compared to previously-circulating variants the vaccines were specifically designed to protect against, Russo explained. However, he said, “the likelihood that the vaccine is going to help prevent severe disease, hospitalization, and death is quite high.”

Are There Any New Symptoms Associated with the XEC Variant?

Unfortunately, if you’re feeling sick, you probably won’t be able to tell if you’ve come down with XEC or a different COVID strain. For now, there doesn’t seem to be any distinct or unique symptoms associated with the new variant, Russo and Schaffner agreed.

That said, people infected with XEC could experience any of the following known COVID symptoms:

• Fever or chills
• Congestion
• Runny nose
• Cough
• Loss of taste or smell
• Shortness of breath
• Body aches
• Sore throat
• Fatigue
• Nausea
• Vomiting
• Headache
• Diarrhea

If you ever experience trouble breathing, confusion, pain or pressure in your chest, or difficulty staying awake, that could be a sign of an emergency, and you should seek medical care immediately.

If you test positive for COVID, it’s as important as it always has been to stay away from others to protect vulnerable people in your community, experts said. You should also consider whether the antiviral Paxlovid could help you—particularly if you’re at high risk for severe disease—and should start taking the medication sooner rather than later if your doctor recommends it, Russo explained.

But again, since there’s no evidence suggesting the XEC variant will behave in a significantly different way than previous variants, people shouldn’t necessarily be too concerned about its spread.

“The evolution of this virus is going to continue in perpetuity,” Amesh Adalja, MD, a biosecurity and emerging infectious diseases expert at the Johns Hopkins Bloomberg School of Public Health, told Health. “One [variant] is always going to be rising, one is going to be falling—that’s what respiratory viruses do.”