Experts expect the current COVID vaccines to provide strong protection against XEC.Getty Images
This is an update of an article originally published on September 23, 2024.
As the United State gears up for a potential surge of COVID-19 cases during the colder months ahead, health authorities are carefully monitoring the rise of the new coronavirus variant XEC.
According to the latest tracking charts shared by the Centers for Disease Control and Prevention (CDC), the predominant variant is currently KP.3.1.1, which was responsible for an estimated 57 percent of COVID-19 cases during the two-week period ending October 26.
But XEC has risen to the No. 2 spot, causing an estimated 17 percent of cases. It accounted for fewer than 1 percent of cases a month prior.
Eric Topol, MD, director of the Scripps Research Translational Institute in La Jolla, California, recently posted on X (formerly Twitter) that the XEC variant has “the most growth advantage of any circulating [variant].”
How Is XEC Different From the Current Top Variants?
KP.3.1.1 is a close relative of other top variants — KP.2.3, KP.3, and KP.2.
XEC is different from KP.3.1.1. because it is a “recombinant” virus, meaning it incorporates features from two other variants (in this case, KS.1.1 and KP.3.3), explains Peter Chin-Hong, MD, a professor of medicine at the University of California in San Francisco, who specializes in infectious diseases.
He points out that XEC has a mutation in a so-called spike protein that may improve its ability to bind to human cells, which in turn may heighten contagiousness.
Will Vaccines Offer Enough Protection?
Dr. Chin-Hong advises the public to be “curious and vigilant” but not overly worried about XEC: The variant, he says, doesn’t appear to pose a greater health threat than other currently circulating variants.
Although the updated 2024–2025 COVID vaccine was formulated specifically to protect against variants from the recent past, XEC is closely related to those variants, so the vaccine is expected to be effective against XEC as well, according to Chin-Hong.
This is why Chin-Hong and other healthcare providers are emphasizing the importance of vaccination — especially for people who are particularly vulnerable to severe COVID-19 like the elderly or the very immunocompromised. In these groups, immunity from earlier vaccinations or infections will likely have sufficiently worn off by now.
The CDC provides information on how to find a vaccine provider near you.
What Are the Symptoms of the XEC Variant?
If you have any of the signs of COVID-19, the CDC urges getting tested so you can confirm the cause, take steps to avoid passing the sickness to others, and get treatment if needed to reduce the chances of developing severe illness.
Symptoms of XEC haven’t changed from the CDC’s latest list, according to Chin-Hong, and are similar to those of FLiRT variants that drove COVID cases over the summer:
When it comes to shortness of breath, Chin-Hong highlights that this symptom seems to appear more frequently in older or immunocompromised individuals who did not get a vaccine in the last year.
XEC Is the Latest But Not the Last COVID Variant We’ll Ever See
The latest variant is certainly not the last. But increasing community immunity, updated vaccinations, and medicines such as Paxlovid and other antivirals make it unlikely that we will see a pandemic-level rise in serious illness as more variants come along, notes Amesh Adalja, MD, senior scholar with the Johns Hopkins Center for Health Security in Baltimore and a spokesperson for the Infectious Disease Society of America.
“Variants are going to come and go in perpetuity,” he says. “There will always be one variant rising and one falling, basically forever. And respiratory viruses will continually evolve to try and get around some of the immunity that prior infections and vaccinations have engendered.”
Editorial Sources and Fact-Checking
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FDA Approves and Authorizes Updated mRNA COVID-19 Vaccines to Better Protect Against Currently Circulating Variants. U.S. Food and Drug Administration. August 22, 2024.
Don Rauf has been a freelance health writer for over 12 years and his writing has been featured in HealthDay, CBS News, WebMD, U.S. News & World Report, Mental Floss, United Press International (UPI), Health, and MedicineNet. He was previously a reporter for DailyRx.com where he covered stories related to cardiology, diabetes, lung cancer, prostate cancer, erectile dysfunction, menopause, and allergies. He has interviewed doctors and pharmaceutical representatives in the U.S. and abroad.
He is a prolific writer and has written more than 50 books, including Lost America: Vanished Civilizations, Abandoned Towns, and Roadside Attractions. Rauf lives in Seattle, Washington.
