What Are the Symptoms of the New COVID-19 Variant N B.1.8.1?

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On May 30, 2025

Although severe illness from COVID-19 has been on a downward trajectory, the coronavirus still maintains its remarkable ability to mutate.

Thousands of variants have emerged since the start of the pandemic.

Now there’s a new one: NB.1.8.1.

The World Health Organization (WHO) recently began monitoring NB.1.8.1 due to rising global case counts, particularly in China and Hong Kong, where hospitalizations due to COVID-19 are increasing.

The latest available WHO data from 22 countries shows that the prevalence of NB.1.8.1 has quadrupled over the last month, jumping from 2.5 percent to 10.7 percent of virus samples over the four weeks ending April 27.

NB.1.8.1 COVID Variant Could Fuel Summer Surge

In the United States, the NB.1.8.1 variant has been detected in several U.S. airports by the Centers for Disease Control and Prevention (CDC).

But experts think the new variant may lead to an escalation in U.S. cases in the weeks ahead, according to Amy Edwards, MD, an assistant professor at the Case Western Reserve University School of Medicine in Cleveland who specializes in pediatric infectious diseases.

“There have been late spring or summer surges in past years, and this variant could push one this year,” says Dr. Edwards.

On a positive note, public health officials are not expecting a rise in severe illness due to this mutation, despite reports of more hospitalizations in Asia.

The WHO reports that routine clinical surveillance does not indicate any signs of increased severity associated with NB.1.8.1 compared with previously circulating variants.

“Currently there is no evidence of increases in indicators like COVID-19-related ICU admissions and deaths per hospitalizations, or all-cause mortality,” writes the global health organization.

Vaccination Provides Protection Against NB.1.8.1

Based on all the preliminary information about NB.1.8.1, vaccination should continue to protect people from severe illness even if the virus is more transmissible, says Mark Rupp, MD, a professor in the division of infectious diseases at the University of Nebraska Medical Center in Omaha .

“NB.1.8.1 is from a lineage of omicron, so we expect that it is related closely enough to variants targeted by the current vaccine and the vaccine proposed for the coming season,” says Dr. Rupp.

He suggests that keeping up with vaccination can help limit the severity and spread of illness.

“These spikes of activity with the virus usually correspond with a new variant that’s more transmissible and a period of time when people’s immunity has waned so they are more susceptible to the virus,” says Rupp.

He adds that it’s important for vaccines to remain widely available and reimbursed by insurance plans — particularly for people who are at high risk of severe illness and who want to do what they can to protect themselves.

What Are the Symptoms of NB.1.8.1?

Symptoms of infection from the latest variant appear to be the same as previous iterations of the virus, according to Rupp. These include:

Nasal congestion or runny nose
Sore throat
Fatigue
Headache
Cough
Muscle or body aches
Fever or chills
Nausea or vomiting
Diarrhea
New loss of taste and smell
Shortness of breath or difficulty breathing

If you’re showing signs of illness, Edwards recommends taking measures to prevent spreading it to others — such as staying home, wearing a mask, and avoiding crowded venues — especially for those who are most vulnerable.

“COVID is never going away,” says Edwards. “We need to do what we can to protect ourselves and others from this and other major respiratory illnesses.”