If you have woken up recently feeling like you are swallowing broken glass, you are not alone. A sharp, agonizing sore throat—colloquially dubbed the "razor blade" throat—has become the hallmark symptom of the newest COVID-19 variant sweeping across the United States this winter. Officially designated as NB.1.8.1 and nicknamed "Nimbus," this Omicron subvariant has rapidly unseated previous strains to become the dominant driver of the 2026 winter surge.
The Rise of Nimbus (NB.1.8.1) in 2026
As of mid-January 2026, health officials confirm that NB.1.8.1 now accounts for a significant majority of new COVID-19 cases. Emerging from the Omicron lineage—specifically descending from the JN.1 family—Nimbus has evolved to be exceptionally transmissible. Following holiday gatherings and winter travel, case numbers have climbed steadily, reminiscent of the viral patterns seen in previous post-holiday seasons.
Viral evolution experts note that Nimbus carries specific mutations that allow it to bind more tightly to ACE2 receptors in the upper respiratory tract. This biological "stickiness" explains why it spreads so efficiently in social settings, moving through households and workplaces at a rate estimated to be 2.5 times faster than its predecessors. While the variant's rapid spread is concerning, the World Health Organization (WHO) and CDC emphasize that it does not currently appear to cause more severe disease or higher hospitalization rates than earlier Omicron waves.
Why the "Razor Blade" Throat?
The defining characteristic of the Nimbus COVID variant 2026 is the intensity of the throat pain it causes. Unlike the scratchy or mild irritation associated with early pandemic strains, patients infected with NB.1.8.1 report a stabbing, burning sensation often described as "swallowing razor blades."
Why is this happening? Medical experts suggest that because NB.1.8.1 replicates aggressively in the mucosal tissues of the throat and nasal passages, it triggers a localized but intense inflammatory response. This inflammation leads to the severe pain patients are experiencing, often before other symptoms like fever or cough fully develop. This symptom is so distinct that many clinicians now consider a severe sore throat a primary red flag for Nimbus infection, even before testing.
NB.1.8.1 vs. Flu Symptoms
Distinguishing Nimbus from other winter respiratory viruses can be tricky, but there are subtle differences. While the flu often hits with a sudden high fever and full-body exhaustion (
