With fall officially underway and chilly weather sweeping across much of the United States, COVID-19 cases are on the rise. New variants have fueled the surge, and the ‘razor-blade’ throat symptom in particular could signal infection from the highly transmissible Nimbus strain. The latest data from the US Centers for Disease Control and Prevention’s Wastewater surveillance suggests the viral activity levels are ‘very high’ in Utah, Nevada, Connecticut, and Delaware, while Washington, New York, California, Minnesota, Montana, and North Carolina, among others, report high viral activity levels. This spike in cases comes amidst the growing confusion around who is eligible to get the updated COVID-19 vaccines this fall.
New covid strains emerge
The Nimbus variant, also known as NB.1.8.1, is a subvariant of the Omicron (JN.1-lineage) variant of the SARS-CoV-2 virus that causes COVID-19. This variant was first detected in China in early 2025. Nimbus is highly transmissible, which means it spreads faster than the earlier COVID-19 variants. This is because the virus has been found to have mutations that help it bind more easily to human cells, according to Stony Brook Medicine.
What is the razor blade throat?
Sore throat is known as one of the first signs of COVID-19 infection, and now it is specifically linked with Nimbus, the newest strain. Though Nimbus shares many symptoms with previous COVID variants, this one distinct symptom stands out. A razor blade throat. What is it? It feels like a sharp, ‘stabbing sore throat,’ especially when swallowing. A razor blade throat is one of the earliest signs of the infection.
What are the common symptoms of Nimbus?
Other than the razor blade throat, the symptoms are mostly mild and are similar to other respiratory illnesses. The common symptoms of Nimbus include:
- Razor blade throat
- Fatigue
- Mild cough
- Nasal congestion or a runny nose
- Fever and muscle aches
- Sneezing
- Digestive symptoms (nausea or diarrhea)
Nimbus variant spreads fast
The new Nimbus variant is highly transmissible. This variant attaches strongly to a part of our cells called the ACE2 receptor, the same spot all COVID-19 variants use to enter. It effectively infects cells, which is up to 2.5 times more compared to its previous leading variants.
Who is at risk?
While anyone can catch the variant, especially as the weather gets cooler, some are more susceptible to the virus than others. People who are at higher risk include:
- Older adults
- Those with chronic conditions such as heart disease, diabetes, or lung disorders
- Individuals with a compromised immune system
- Unvaccinated individuals
- Children
- Pregnant women
How to reduce your risk?
The best way to prevent and also reduce the impact if infected is to get vaccinated. Also, simple steps such as good hygiene, wearing a mask in crowds, and maintaining distance from those infected can help.
