New COVID Variant NB.1.8.1 ‘Nimbus’ Spreads in the U.S.
A highly transmissible new COVID-19 variant, NB.1.8.1, also known as “Nimbus,” is now responsible for 37% of COVID cases in the United States, according to the CDC. The variant, an Omicron subvariant, has been rapidly spreading since it was first detected in late March 2025. As the variant continues to gain ground, it’s crucial for individuals to recognize its symptoms and stay informed about preventive measures.
What is the Nimbus Variant?
The NB.1.8.1 variant was first identified through airport screening programs for international travelers in March 2025. It has since spread to at least 14 U.S. states and several other countries. Nimbus is characterized by mutations in its spike protein, which may increase its transmissibility. The World Health Organization (WHO) classified Nimbus as a “variant under monitoring” due to its rapid spread and potential for immune evasion.
As of June 7, 2025, NB.1.8.1 accounts for 37% of U.S. COVID cases, making it the second-most common variant after LP.8.1, which leads with 38% of cases.
Symptoms of the Nimbus Variant
The symptoms associated with Nimbus are similar to those of recent Omicron subvariants, including:
- Sore throat (described as “razor blade throat” by some individuals)
- Cough
- Runny nose or congestion
- Shortness of breath
- Fever or chills
- Headache
- Body aches
- Fatigue
- New loss of sense of smell or taste
Informal reports linked to the Nimbus variant have highlighted the severity and frequency of a sore throat described as a “razor blade” feeling, despite the symptoms being familiar.
Is Nimbus More Transmissible?
Research suggests that NB.1.8.1 may be more transmissible than previous strains, likely due to its spike protein mutations, which could allow it to bind more effectively to human cells. While studies are ongoing, experts believe the variant’s rapid spread and ability to evade some immunity make it a significant concern for public health.
What to Do if You Experience Symptoms
Anyone experiencing symptoms consistent with COVID-19 should get tested and isolate until results are available. The CDC recommends wearing masks, especially in crowded or poorly ventilated areas, and practicing good hygiene to reduce transmission.
Vaccination and Protection
The current COVID vaccines are expected to remain effective against NB.1.8.1, helping prevent severe illness, hospitalization, and death. Health experts recommend staying up-to-date with vaccinations, particularly for individuals in high-risk groups, such as those over 65 or immunocompromised.
The 2024-2025 vaccines remain available, but the 2025-2026 vaccine, targeting newer variants like LP.8.1, will be released this fall. The CDC also suggests that high-risk individuals consider getting vaccinated again if they haven’t received a dose in the last six months.
Looking Ahead: Will Nimbus Lead to a Summer Surge?
The U.S. has seen consistent COVID-19 surges in summer since 2020, and experts predict that the spread of Nimbus may contribute to an increase in cases in the coming months. Although the symptoms are familiar, informal reports linked to the Nimbus variant have highlighted the severity and frequency of a sore throat described as a “razor blade” feeling.
As Nimbus continues to spread, it’s essential to stay vigilant, especially with increased travel and social gatherings expected in the summer months. Stay informed about the symptoms, take preventive measures, and ensure you’re up-to-date on your COVID-19 vaccinations to help protect yourself and others from the evolving virus.
More…
- https://www.thestar.com/news/canada/will-the-new-covid-19-variant-that-s-on-the-rise-give-you-a-razor/article_d4f6e079-1eed-4e67-b317-b4a8f23ab6da.html
- https://www.today.com/health/coronavirus/new-covid-variant-nb181-nimbus-symptoms-rcna212304
- https://www.forbes.com/sites/brucelee/2025/06/14/razor-blade-throat-symptoms-as-nimbus-covid-19-variant-spreads
