A new COVID-19 variant, NB.1.8.1, is spreading globally and has now been detected in the U.S., raising concerns of a possible rise in cases this summer.
The World Health Organization (WHO) is monitoring the variant, which has appeared in parts of Europe, Southeast Asia, and the Americas. Early data suggests NB.1.8.1 is more transmissible than the current dominant strain, LP.8.1, though not more likely to cause severe illness or evade immunity from vaccines or past infections.
“It’s important to track, but it hasn’t shown signs of causing a major surge in U.S. cases,” said Dr. Andrew Pekosz, virologist at Johns Hopkins Bloomberg School of Public Health.
NB.1.8.1 is part of the omicron family, which has dominated globally since late 2021. The variant has become widespread in China and is slowly emerging in the U.S., with fewer than 20 sequences confirmed so far, according to the CDC. Cases have been found in Arizona, Ohio, and Rhode Island.
Although the variant is not yet prevalent in the U.S., infectious disease experts warn that waning immunity and low booster uptake—fewer than 25% of adults have received the latest shot—could make the population more vulnerable.
“We haven’t had a major COVID wave in a while,” said Dr. Thomas Russo of the University at Buffalo. “This combination of low immunity and a more transmissible variant could bring a summer bump.”
COVID cases tend to rise in both summer and winter, regardless of variant, said Dr. Scott Roberts of Yale School of Medicine. “We may see a mild to moderate uptick,” he said.
Vaccines are updated each fall, and the FDA has asked manufacturers to target LP.8.1 for the next round. Early data suggests the updated shots from Pfizer and Moderna will also offer protection against NB.1.8.1.
However, the FDA plans to limit updated vaccine eligibility to older adults and medically vulnerable younger people. The CDC recently stopped recommending COVID vaccines for healthy children and pregnant women—prompting concern from some doctors.
“We know immunity fades and the virus changes,” said Russo. “Even people with multiple shots may not be fully protected if they haven’t been boosted recently.”
Doctors recommend eligible individuals get a booster now, especially since NB.1.8.1 is genetically similar to the JN.1 variant targeted by current vaccines.
Whether NB.1.8.1 becomes the dominant strain in the U.S. remains uncertain, but experts say staying informed and up to date on vaccines remains the best defense.
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