A recent COVID‑19 variant, officially known as NB.1.8.1 and informally dubbed Nimbus, has gained attention due to one particularly striking symptom: a sore throat so intense that patients describe it as feeling like swallowing razor blades or shards of glass. This vivid description has been reported by physicians and patients across regions like the UK, India, Southeast Asia, and parts of the U.S.
Though severe sore throats are not new to COVID, the intensity with Nimbus seems notably higher. However, experts warn this might reflect media emphasis rather than a new medical red flag. Previous Omicron subvariants also triggered painful sore throats—one systematic review found sore throat in up to 70% of cases —suggesting Nimbus is part of an evolving but familiar viral pattern.
Global Spread and Prevalence
- First Identified: January 2025, likely in China and other parts of Asia.
- WHO Classification: Labelled on May 28, 2025, as a “variant under monitoring”, implying it’s being observed but not yet a major concern.
- Global Penetration: By mid‑May 2025, Nimbus composed nearly 11% of sequenced cases worldwide.
- Regional Hotspots: Coverage includes the eastern Mediterranean, Southeast Asia, the western Pacific, parts of North America, and Europe.
- United States: The CDC reported Nimbus made up about 37% of national samples by early June 2025. It’s prevalent in states such as California, New York, Illinois, Texas, Washington, and Virginia.
Is Nimbus More Dangerous?
No clear indication of increased severity:
- Hospitalizations and death rates have stayed largely consistent, with no noticeable spikes in countries like the U.S. or western Pacific countries.
- Despite its rapid spread, experts emphasize that symptoms remain broadly similar to previous Omicron strains: fever, chills, cough, shortness of breath, fatigue, and loss of taste or smell.
- A lab-based study hints at slightly higher transmissibility, due to spike‑protein mutations and tighter binding to human ACE2 receptors—but the full implications for real-world infection are still unclear .
Why Is This Happening? The Nature of Viral Evolution
COVID‑19 variants continue to evolve—acquiring mutations that enhance transmission—even when disease severity doesn’t escalate . Nimbus, like its predecessors, demonstrates this evolutionary trajectory. Infectious disease specialists describe it as “evolution unfolding in front of our eyes” .
What Should You Do? Prevention, Vaccines, and Awareness
- Don’t dismiss sore throats—especially sudden, intense ones. Get tested to rule out COVID‑19, the flu, strep, or other infections.
- Vaccines remain effective. Despite policy shifts (such as U.S. Health Secretary Robert F.
- Kennedy Jr.’s recent statement against shots for healthy kids and pregnant women), experts confirm current vaccines continue to protect against severe illness, hospitalization, and death from Nimbus.
Boost immunity with updates. CDC guidelines emphasize updated 2024–2025 COVID vaccines, especially for high‑risk groups. Pregnant women also benefit—not only themselves but also their newborns.
Practice proven safeguards:
- Hand hygiene, masks in crowded or high-risk areas, and proper ventilation remain key
- Use rapid at‑home tests if symptomatic, and consider antivirals like Paxlovid early if at higher risk.
Older adults and immunocompromised individuals should stay extra vigilant, mask in public, and discuss boosters with healthcare providers.
Nimbus (NB.1.8.1) is a fast‑spreading Omicron descendant notable for intense sore throats, though it’s not inherently more dangerous than previous COVID variants. Although hospitalizations haven’t surged, the variant’s prevalence—especially in young summer travelers—warrants public health attention. Vaccines and basic precautions remain our strongest defense.
