New COVID Variant Confirmed In CA: Here's What To Know

CALIFORNIA — A new variant of COVID-19, which is currently dominant in China, is circulating in other parts of the world, including the United States, and it could affect California residents, health officials warn.

The World Health Organization said the variant, called NB.1.8.1, is primarily on the rise in the eastern Mediterranean, Southeast Asia, and western Pacific regions. U.S. airport screenings detected it in travelers arriving from those regions to destinations in California, Washington state, Virginia, and New York. A handful of states — Rhode Island, Ohio, and Arizona — have reported NB.1.8.1 cases.

California's first local case of the NB 1.8.1 was confirmed by scientists at the Stanford Clinical Virology Laboratory earlier this week. Officials in California are monitoring the variant, and in the meantime, federal officials are recommending that fewer people get vaccinated against the disease.

However, experts say the variant could take hold because it’s been a while since the U.S. saw a COVID wave, lowering protection from having had it, and because less than a quarter of U.S. adults are current on their vaccinations and boosters.

“It may, unfortunately, come back with a little bit of vengeance on us. Let’s hope that doesn’t happen, but I am concerned that we may be setting ourselves up for that with this combination of factors,” Dr. Thomas Russo, chief of infectious diseases at the University at Buffalo Jacobs School of Medicine and Biomedical Sciences, told ABC News.

In California, the COVID-19 vaccine rate among children ages 6 months to 17 years old was 6.2 percent through March 2025, according to data from the Centers for Disease Control and Prevention. That number was a 0.1 percent increase from the previous year.

Adults 18 and older saw a similar increase through March 2025, with a 17.1 percent COVID-19 vaccine rate compared to 17% in 2024.

The largest vaccination rate came from those 65 years and older, who have been getting vaccinated at a higher rate than last year. Through March 2025, the COVID-19 vaccination rate amongst that age group was 40.7 percent compared to 38.5 percent the previous year.

SEE ALSO: COVID Vaccine Rule Changes Proposed: What To Know In California

Data from the CDC shows the weekly number of emergency doctor visits in California resulting in a COVID diagnosis has remained relatively consistent with last year. In May 2024 and 2025, about 0.4 percent of patients visiting an emergency room tested positive for COVID.

There were significantly fewer COVID-related deaths through May 2025 compared to 2024, CDC data shows. There were just 1,900 COVID-related deaths in California from January through May 2024. Through the same timeframe in 2025, that number was just over 742, according to CDC data.

The new variant is yet another of the hundreds of descendant subvariants of the omicron variant, detected in 2021. None has led to the rise in COVID cases seen during the height of the coronavirus pandemic. Although the currently available vaccine is effective against the new variant, some of its mutations could make it more difficult to treat, according to the WHO.

The variant also appears to be more transmissible than the current dominant strain, LP.8.1, both in the United States and worldwide. It could easily exploit waning immunity, Dr. Todd Ellerin, chief of infectious diseases at South Shore Health, told ABC News.

“Remember, we’ve seen summer surges,” he said. “One thing that COVID has done is it's been able to surge in the summer, and it’s been able to surge in the winter, and that’s very different than respiratory viruses we’ve dealt with in the past. But we still don't know if this is going to be the virus that leads to a summer surge, it's just too early to know.”

There is no evidence to suggest NB.1.8.1 causes more severe illnesses than other circulating variants.

“It’s an important one to track, but it doesn’t show any signs so far of being able to drive a large surge in COVID-19 cases — at least in the U.S.,” Andrew Pekosz, a virologist at Johns Hopkins Bloomberg School of Public Health, told NBC News.

There hasn’t been enough activity for NB.1.8.1 to show up on the Centers for Disease Control’s COVID dashboard. A spokesperson for the agency told NBC there have been fewer than 20 sequences of the variant reported in the U.S. to date.

“Whether it gets a foothold in this country and it becomes our new dominant variant or not remains to be seen,” the University at Buffalo Jacobs School of Medicine and Biomedical Sciences’ Russo told NBC.

The variant arrives as the United States’ official stance on COVID-19 vaccination is changing. On Tuesday, Health Secretary Robert F. Kennedy Jr. announced that COVID-19 shots are no longer recommended for healthy children and pregnant women — a move immediately questioned by several public health experts.

"I couldn't be more pleased to announce that as of today the COVID vaccine for healthy children and healthy pregnant women has been removed from the CDC recommended immunization schedule," Health and Human Services Secretary Robert F. Kennedy Jr. announced on X earlier this week. "We're now one step closer to realizing President Trump's promise to make America healthy again."

Previous federal policy recommended an annual COVID shot for all Americans six months and older.

But the new FDA urges companies to conduct large, lengthy studies before tweaked vaccines can be approved for healthier people.

"For many Americans we simply do not know the answer as to whether or not they should be getting the seventh or eighth or ninth or tenth COVID-19 booster,” said Vinay Prasad, who joined the FDA earlier this month. He previously spent more than a decade in academia, frequently criticizing the FDA's handling of drug and vaccine approvals.

The Associated Press contributed to this report.