New COVID-19 Variant Nimbus Arrives in the U.S.

The World Health Network (WHN) has identified the COVID-19 variant NB.1.8.1, also called Nimbus, as the cause of the virus’s resurgence in China and several other Asian countries. Health experts in Europe have reported a slow increase in the variant there and are predicting more cases.

This variant, a descendant of the Omicron subvariant JN.1, has been designated a variant under monitoring by the World Health Organization (WHO) due to its increasing global presence and potential implications for public health. 

The U.S. Centers for Disease Control and Prevention (CDC) reported that NB.1.8.1 already represents around one-third of new COVID-19 cases as of June 7. A month before, Nimbus only represented 5% of new cases. In the U.S., it has been traced to New York, California, Arizona, Ohio, and Rhode Island, according to Gingko Bioworks, the CDC’s airport testing partner.

Still, WHN data does not show an increased severity compared to previously circulated variants. Given the strain is outcompeting previous variants, it is possible Nimbus could be more contagious, but health experts said no research shows the virus spreads differently than other variants. Commonly reported symptoms include a severe sore throat described as “razor-blade throat, fatigue, mild cough, fever, muscle aches, and congestion.”

WHN emphasized the emergence of this new variant in the summer contradicts the notion that Covid-19 is a cold-weather seasonal illness.