Nimbus COVID variant is
spreading across the US
What is Nimbus (NB.1.8.1)?
- A descendant of Omicron, first detected in January 2025, and officially designated a “variant under monitoring” by the WHO as of May 23, 2025
- Has mutations in the spike protein that enhance transmissibility and may partially evade existing immunity—but so far, there's no evidence of increased severity
How widespread is it?
- Now accounts for an estimated 37% of U.S. COVID cases for the two weeks ending June 7, 2025 (up from ~15% in late May) .
- Detected in at least 14 U.S. states—including California, New York, New Jersey, Illinois, Massachusetts, and others
Symptoms to look out for
- Similar to previous Omicron strains: fever, cough, congestion, fatigue, muscle aches, loss of taste/smell .
- A standout symptom: an intense sore throat described as “razor blade throat,” likened to swallowing glass—even though sore throat has always been common
Severity and protection
- Currently not causing higher hospitalization or death rates, and no evidence of increased virulence .
- Vaccines (2024–25) and treatments like antivirals remain effective at preventing serious illness .
- With many people 6+ months out from vaccination, susceptibility is rising—especially amid increased summer travel and gatherings
What you can do
- Be "COVID street smart"—avoid high-risk exposures if you're older, immunocompromised, or have chronic conditions
Bottom line
- Nimbus is spreading fast, now a major driver of U.S. cases, but it’s not more dangerous than other Omicron variants. Vaccination, good hygiene, and smart precautions remain your best line of defense