Nimbus COVID variant is spreading across the US. It’s likely in CT, health experts say

CT Insider – Friday, June 13, 2025
By Lilli Iannella

Over the past few months, a new COVID-19 variant has been spreading across the United States. It’s called NB.1.8.1, nicknamed “Nimbus,” and as of the first week of June, it’s the second most common strain of COVID currently spreading across the nation, according to the United States Centers for Disease Control and Prevention.

According to sequences shared with the Global Initiative on Sharing All Influenza Data (GISAID) database, which stores influenza virus data and is utilized by the World Health Organization (WHO), as of Friday, Nimbus has been detected in at least 14 states. This includes New York, New Jersey, Massachusetts and Rhode Island.

“Basically we’re surrounded on all sides. It would be hard to think that some of this new variant hasn’t crept into the state of Connecticut, particularly Fairfield County where we have so many commuters to New York and New Jersey,” said Dr. Jo-Anne Passalacqua, an infectious disease specialist at St. Vincent’s Medical Center who also runs a private practice in Fairfield.

As of the first week of June, just under 300 people in Connecticut had reported testing positive for any strain of COVID, according to the Connecticut Department of Health.

Passalacqua, as well as Yale School of Medicine assistant professor Dr. Scott Roberts, suspects COVID cases to be underreported. COVID testing surveillance is not as robust as it used to be, Roberts said. The main sources of data come from wastewater testing from major cities, Passalacqua said. In Connecticut, the wastewater viral activity level for COVID is currently “very low,” according to the CDC.

But that doesn’t mean COVID, specifically the Nimbus strain, doesn’t have the potential to surge this summer, which Passalacqua and Roberts speculate could occur.

Nimbus is a descendant of the Omicron variant of the COVID-19 virus, Roberts said, meaning it’s mutated from previous variants.

“It’s all within that same family tree. And this is sort of the natural progression of a lot of these variants where we don’t see these massive shifts in the genomes; it’s more of this kind of slow creeping along changes over time,” Roberts said.

Late last month, the WHO labeled it as a “variant under monitoring,” one of six COVID-19 currently circulating across the world. Specifically in the U.S., Nimbus was first detected in March, Passalacqua said.

Nimbus symptoms and severity are very similar to those of other COVID strains, Passalacqua and Roberts said.

“What seems to be unique about this Nimbus strain is that it’s highly contagious, perhaps a bit more contagious than some of the prior strains. Hence, the percentage of patients they’re finding this Nimbus strain has steadily increased since it was first detected,” Passalacqua said.

What are Nimbus COVID variant symptoms?

According to the CDC, COVID symptoms for variants like Nimbus include fever, chills, cough, shortness of breath, runny nose, sore throat and new loss of taste or smell. Specifically for the Nimbus variant, Roberts said he’s heard the phrase “razor blade sore throat” be used, but he said there isn’t enough data to suggest that yet.

“The hallmark of COVID that distinguishes it from others is the loss of taste and smell,” Roberts said. “But otherwise, as far as I can tell, it’s the same kind of expected symptoms that we’ve had with prior COVID variants.”

In severe cases, symptoms include trouble breathing, chest pain, confusion, inability to stay awake and pale skin, according to the CDC.

How can you protect yourself against the Nimbus COVID variant?

Nimbus, likewise to other COVID variants, is spread through airborne virus droplets of an infected person through actions like sneezing, coughing and singing that can also fall on surfaces like countertops, sinks or door handles, Passalacqua said.

To avoid catching the Nimbus variant or any COVID variant, Passalacqua and Roberts recommend frequent hand washing, avoiding people who are sick and wearing a mask in high risk settings such as an airport, public transportation, grocery stores, theaters and concert venues.

Both Passalacqua and Roberts recommended people get vaccinated against COVID.

“Vaccines are really one of the best tools we have to prevent severe disease,” Roberts said. “For those high risk people, a vaccine is going to be better than any treatment we offer.”

Those at high risk are people over 65, pregnant women and those with underlying medical conditions like chronic lung disease or who are immunocompromised, according to the CDC.

The virus is also spreading as immunity wanes for people who got vaccinated in the fall or were infected with the virus in the winter, Roberts said. Passalacqua recommends people, especially those having compromised immune systems or with lung disease, receive updated COVID booster vaccines.

“As an infectious disease practitioner who lived through the pandemic and was at the bedside of many, many sick patients, I would say the vaccine literally changed the course of the pandemic and saved many, many lives,” Passalacqua said. “I would say that vaccine saved far more lived than we lost due to any vaccine side effect.”

With children being out of school, families traveling and more during the summertime, both Passalacqua and Roberts think it is possible the nation could experience a surge in the Nimbus variant, as has been seen with other variants in years before.

“All of the gathering and movement of people that occurs in the summertime seems to be the perfect storm for surges in COVID,” Passalacqua said.

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