As summer approaches, health officials worldwide are closely monitoring a new COVID-19 variant known as NB.1.8.1, which is rapidly gaining ground across multiple continents. This subvariant, part of the Omicron lineage, has been detected in over 20 countries, including the United States, the United Kingdom, China, Australia, and Thailand. Experts warn that NB.1.8.1 could trigger a fresh wave of infections, particularly in regions like North Carolina, where its arrival seems imminent.
According to the World Health Organization (WHO), NB.1.8.1 now accounts for just over 10% of global COVID-19 infections, marking a significant shift in the viral landscape. The variant was first recognized in early 2025, with the earliest known cases appearing at the end of April. In the United States, the Centers for Disease Control and Prevention (CDC) has identified only about 20 cases so far, including 14 in Washington state. The Washington Department of Health reported that these samples were collected between April 7 and May 20, 2025, with some cases detected in travelers at Seattle-Tacoma International Airport as part of the CDC's variant tracking program.
Despite the relatively low number of confirmed cases in the U.S., the variant's rapid spread elsewhere raises concerns. Dr. David Weber, an infectious disease specialist at the University of North Carolina School of Medicine, noted that while no confirmed cases have yet been reported in North Carolina, it is likely only a matter of time before the variant arrives. "I don’t expect it’ll be a surge quite like some of the surges we’ve had in the past," Weber said, "but we know we’ve had other surges in the summer. These respiratory viruses, COVID, flu, and RSV, generally, are more transmittable in the winter than in the summer, because the virus survives better at low temperatures, low humidity, and people are indoors more. But we’ve already seen COVID surges in the summer."
NB.1.8.1 carries mutations on its spike protein that enhance its ability to bind to receptors in the nasal and lung passages, making it more contagious than previous variants. This mutation likely contributes to its growth advantage and ability to displace other circulating strains. The WHO has designated NB.1.8.1 as a "variant under monitoring" due to its rising prevalence, though current data do not show an increase in disease severity or hospitalizations linked to this variant.
Symptoms associated with NB.1.8.1 are similar to those seen with earlier Omicron subvariants. These include a persistent dry cough, blocked or runny nose, fatigue, fever, chills, sore throat, muscle aches, headache, and in some cases, gastrointestinal symptoms such as diarrhea, constipation, and nausea. The WHO and health experts emphasize that most people infected with NB.1.8.1 can continue their daily activities, although they may feel more tired than usual. However, they urge individuals to seek immediate medical attention if they experience severe symptoms such as chest pain, difficulty breathing, confusion, or loss of consciousness.
Despite its increased transmissibility, vaccines remain a critical defense against NB.1.8.1. The 2024-2025 vaccines were specifically designed to target the Omicron JN.1 family, from which NB.1.8.1 descends. Experts, including Dr. Weber, affirm that these vaccines continue to offer strong protection against serious illness, hospitalization, and death. He recommends that most people wait until the fall to receive their next booster shot, as mRNA vaccines typically provide protection against infection for about three months and against severe disease for six months. However, individuals who are older or immunocompromised should consider getting vaccinated sooner and then again in the fall.
Vaccination sites across the U.S., including pharmacies such as CVS and Walgreens, grocery and big-box stores like Walmart and Target, and healthcare providers, offer the latest COVID-19 vaccines. Public health officials also stress the importance of other preventive measures such as wearing masks indoors in crowded settings, practicing good hand hygiene, and staying home when feeling unwell. Early antiviral therapies are available and most effective when started within five days of symptom onset for COVID-19, underscoring the importance of prompt testing and treatment.
Tracking the spread of NB.1.8.1 has become more challenging due to a significant decline in community COVID-19 testing and a shift towards at-home antigen tests, which are less likely to be reported to health authorities. This trend complicates efforts to accurately assess infection rates and variant prevalence. Nevertheless, surveillance programs like the one conducted by Ginkgo Bioworks at Seattle-Tacoma International Airport and the U.S. Air Force School of Medicine continue to play vital roles in identifying emerging variants.
Globally, NB.1.8.1 has been detected in countries across Asia, Europe, and Oceania. In the United Kingdom, cases have been confirmed in Northern Ireland and Wales, with the variant now making up about 10.7% of all submitted sequences. Experts there have noted the variant’s ability to infect cells more efficiently, which may explain its rapid spread. However, no evidence suggests that NB.1.8.1 leads to more severe illness compared to previous strains.
As the world enters the summer months, the emergence of NB.1.8.1 serves as a reminder that the COVID-19 pandemic remains an evolving challenge. While vaccines and public health measures continue to mitigate risks, health officials urge vigilance and preparedness to respond to potential surges. With the variant’s presence confirmed in multiple states and countries, individuals are encouraged to stay informed, adhere to recommended precautions, and consult healthcare providers about vaccination and treatment options.
In the face of this new variant, the collective efforts of governments, scientists, healthcare workers, and the public will be crucial to navigating the next phase of the pandemic. As Dr. Weber succinctly put it, "We are not out of the woods yet, but with the tools we have, we can manage this variant effectively and protect our communities."
