Super Contagious COVID-19 Variant Gains Ground in New York, Prompts Summer Surge Concerns

A recently identified COVID-19 variant, NB.1.8.1, is beginning to circulate more widely in the United States and internationally prompting heightened attention from public health authorities. Detected initially in January 2025, this new strain is now under surveillance as experts monitor its potential to fuel a rise in infections during the summer months.

NB.1.8.1, a sublineage of the Omicron variant, has already shown rapid growth in parts of Asia and is now appearing in countries across Europe, North America, and Australia. According to the World Health Organization (WHO), as of mid-May this strain has been found in at least 22 nations.

In the U.S., the variant has been picked up through airport screening of international travelers, with confirmed cases in states such as California, Virginia, Washington, and New York. Washington State alone reported 14 new cases in early June. Additional reports have come from Ohio, Rhode Island, and Hawaii.

The WHO’s technical advisory group has designated NB.1.8.1 as a "variant under monitoring" due to its increasing global footprint. Though the agency currently considers the public health risk to be low, it cautions that the strain contains mutations that could improve its ability to spread.

Data collected from GISAID, a global virus tracking database, show that NB.1.8.1 made up just 2.5% of COVID-19 samples worldwide in late March. By the end of April, that figure had jumped to over 10%, indicating a rapid uptick in prevalence.

While early evidence suggests that NB.1.8.1 does not cause more severe illness than previous variants, it may be more contagious. Common symptoms remain consistent with other strains such as fatigue, body aches, sore throat, fever, and congestion, but the variant’s mutations might help it bypass immunity from vaccines or prior infections.

Despite these mutations, health professionals say current COVID-19 vaccines are still believed to offer protection against both symptomatic and severe illness caused by NB.1.8.1.

NB.1.8.1 joins several other variants under monitoring including KP.3, KP.3.1.1, LB.1, XEC, and LP.8.1. The latter, while once more dominant in the U.S., is now reportedly declining in circulation.

Though a summer surge has not yet materialized, public health officials remain worried. As of early June, the CDC reports an upward trend in COVID-19 cases in 6 states while 14 are experiencing a decline and 25 show no significant change.

Super Contagious COVID-19 Variant Gains Ground in New York, Prompts Summer Surge Concerns