A new Covid variant is making headlines for a symptom that sounds like it’s straight out of a horror movie: a searing sore throat that feels like it’s lined with razor blades.
The variant, known as NB.1.8.1, or “Nimbus,” is now being tracked by the World Health Organization. According to Salon, it already makes up more than 10 percent of cases in Asia and has been detected in the U.S., Europe, and Canada.
So, what should you know? From symptoms to prevention tips, here’s what this latest mutation means as Covid continues to evolve.
What is the NB.1.8.1 Covid variant?
NB.1.8.1, a spinoff of the Omicron strain, was first identified in January 2025 and has been steadily spreading since. It evolved from XDV.1.5.1 and is now on the World Health Organization’s radar as a “variant under monitoring” due to its growing global presence.
The earliest surge tied to NB.1.8.1 was reported in China, but it didn’t take long to spread. By late March and early April, U.S. health officials detected it in travelers arriving at California, Washington, Virginia, and New York airports. Additional cases have since been reported in other states, signaling a broader reach.
What are the symptoms of NB.1.8.1?
This particular strain causes “razor blade throat,” or a severe sore throat. Other symptoms reportedly include:
- Congestion
- Fatigue
- A mild cough
- Sore throat
- Fever
- Muscle aches
- Fatigue
- Diarrhea
- Nausea
Is the new Covid variant more contagious?
Health officials in Hong Kong say NB.1.8.1 doesn’t appear to cause more severe illness than previous strains. What sets it apart, though, is how quickly it spreads. The variant’s tighter binding to human cells is what makes it more transmissible, according to microbiology professor Subhash Verma, Ph.D., from the University of Nevada, Reno, who spoke with CBS.
Timing may also be driving the spike in cases, especially in places like China. Covid infections tend to rise during the summer months — and this year is shaping up to follow that pattern. While the World Health Organization currently assesses the global risk as “low,” experts warn that NB.1.8.1 could fuel a summer surge.
“I know that everybody wants to forget about this disease, but it’s not going to allow us to,” Janko Nikolich, MD, Ph.D., professor and chair of the Department of Immunobiology at the University of Arizona College of Medicine, told ABC Action News.
Do the current Covid vaccines protect against this new variant?
The World Health Organization says the current Covid vaccines should still protect against the NB.1.8.1 variant. But there’s a catch: Getting boosters might become more difficult. The Trump administration plans to limit booster shots mainly to older adults and those with certain health conditions. And Health and Human Services Secretary Robert F. Kennedy Jr. just announced that the CDC will no longer recommend routine Covid shots for healthy kids and pregnant women, even though pregnancy remains a high-risk factor for severe complications.
Alongside vaccination, practicing good hygiene, such as thorough handwashing and covering your mouth when coughing or sneezing, remains crucial. And if you’re going to be out in public, it might be worth dusting off that pack of N95 masks you thought you’d never need again. Staying informed and taking simple precautions can go a long way in keeping you and those around you safe.
