A new COVID-19 strain identified just months ago has surged to become the second-most dominant variant across the United States. First detected in China this January, NB.1.8.1 represented nearly zero U.S. infections until May. By early June, CDC projections indicate it accounts for 37% of domestic cases—a dramatic spike reflecting its rapid spread.
What Makes NB.1.8.1 Different?
Scientists describe NB.1.8.1 as a "slightly upgraded version" of the currently dominant Omicron subvariant LP.8.1. Microbiology experts note it spreads more efficiently and evades vaccine-induced antibodies better than its predecessor. "This variant demands vigilant monitoring due to its heightened transmissibility and immune evasion," stated University of Nevada researcher Subhash Verma. Globally, it represented 10.7% of cases by mid-May.
Current Prevalence and Growth
CDC data reveals LP.8.1 (Omicron) remains the top U.S. strain at 38%, closely followed by NB.1.8.1 at 37%. Other variants like XFG (8%) and XFC (7%) trail significantly. The newcomer's rise has been exponential: after registering 0% of cases in March, it jumped to 2% in April, 5% in early May, and 15% by late May before nearly doubling in early June.
Recognizing Symptoms
While the CDC hasn't designated unique symptoms for NB.1.8.1, common COVID-19 signs include fever, cough, fatigue, sore throat, congestion, and muscle aches. Notably, many patients report an intensely painful "razor blade throat"—a sensation likened to swallowing shards of glass. Medical attention is urgent if breathing difficulties, chest pressure, confusion, or bluish skin discoloration occur.
Vaccine Recommendations and Access Shifts
The World Health Organization affirms existing vaccines remain effective against severe illness from NB.1.8.1. The CDC previously urged all individuals over six months old to receive the 2024–2025 Moderna COVID-19 vaccine, particularly high-risk groups like seniors, immunocompromised people, and pregnant individuals.
However, recent policy changes announced by HHS Secretary Robert F. Kennedy Jr. exclude healthy children and pregnant women from vaccine recommendations. Now, only adults 65+ and those with underlying health conditions are formally advised to vaccinate. This shift may limit access for others, potentially requiring out-of-pocket payments. Health officials warn it could impact vulnerable households and frontline workers seeking protection.
Free Testing Resources
Uninsured Americans can still access no-cost COVID-19 tests through the federal ICATT program. Over 19,000 testing sites nationwide participate—locate options via testinglocator.cdc.gov/Search.
Experts stress vigilance as NB.1.8.1's footprint expands, urging at-risk groups to prioritize boosters and symptom awareness.