WASHINGTON — U.S. health officials said on Monday that a new COVID-19 variant identified as NB.1.8.1 has been detected in multiple states, prompting increased monitoring as authorities assess its spread and potential impact on public health. The variant has been identified through federal surveillance programs and laboratory sequencing, according to the U.S. Centers for Disease Control and Prevention (CDC).
The CDC said cases linked to NB.1.8.1 were first identified through its traveler-based surveillance program at major U.S. airports, with detections reported among international arrivals in states including California, Washington, Virginia and New York. Additional cases have since been reported by health authorities in several other states, officials said.
“CDC is aware of reported cases of COVID-19 NB.1.8.1 and is in regular contact with international partners,” a CDC spokesperson said in a statement cited by multiple U.S. media outlets. The agency added that the number of sequenced U.S. cases remains limited, and details about the variant’s prevalence continue to be evaluated.
The variant has drawn attention after becoming associated with increased COVID-19 activity in parts of Asia, including China and Hong Kong, according to reports from international health authorities and researchers. The World Health Organization has classified NB.1.8.1 as a variant under monitoring and said available evidence suggests it may have a growth advantage over some previously circulating strains.
Preliminary data reviewed by public health agencies indicate that NB.1.8.1 may spread more easily than some earlier variants because of changes in its spike protein. However, officials said there is currently no evidence that it causes more severe disease than other recent Omicron-related lineages.
Federal health officials have also been reviewing vaccine recommendations ahead of the next respiratory virus season. Advisers to the U.S. Food and Drug Administration recently discussed whether future vaccine formulations should target newer circulating variants, including NB.1.8.1 and related strains.
Public health agencies said surveillance efforts remain ongoing through airport screening programs, genomic sequencing and wastewater monitoring systems. Officials urged eligible individuals to remain up to date with vaccinations and said antiviral treatments currently authorized in the United States are expected to remain effective against circulating variants.
As of Monday, officials said the overall public health risk assessment had not changed, though monitoring of NB.1.8.1 continues as additional data become available.
