'About NB.1.8.1, the COVID Variant Surging in Asia'

 A new COVID variant driving a surge of infections in China and other parts of Asia has been detected by U.S. airport screening programs

opens in a new tab or window, and experts say it may drive a summer wave in the U.S.

NB.1.8.1 was recently named a "variant under monitoringopens in a new tab or window" by the World Health Organization, and as of mid-May it represented 10.7% of sequences globally.

"While still low numbers, this is a significant rise in prevalence from 2.5% four weeks prior," the WHO stated.

The dominant strain in the U.S. is currently LP.8.1, which Moderna recently selectedopens in a new tab or window as the strain to be included in its COVID shot for the fall. (Pfizer also selected this strainopens in a new tab or window for its fall booster, but has only applied to European regulators for approval thus far.)

According to the CDC's variant tracker, LP.8.1 has stabilized, and experts expect that it may be on the wane. At the same time, the novel variant XFC appears to be on the rise in the U.S.

Nonetheless, NB.1.8.1 may have "some competitive advantage over the strains that are circulating in the U.S. right now," said James Lawler, MD, MPH, of the University of Nebraska Medical Center's Global Center for Health Security in Omaha. "There seems to be enough escape that it can outcompete [other variants] and probably will establish itself as a dominant strain, as long as another new variant doesn't pop up."

Lawler cited a preprint published in bioRxivopens in a new tab or window earlier this month showing that, among several currently circulating variants, NB.1.8.1 "retained high ACE2 affinity and humoral immune evasion, supporting its potential for future dominance."

It's likely to cause a "pretty sizeable summer wave," Lawler said, given a few conditions. Since COVID-19 came on the scene, the U.S. has generally seen epidemic waves in the winter and summer, "so why should we expect any differently now?" he said.

Also, the winter COVID wave was not that severe, "so we're primed in terms of timing and very low rates of recent vaccination," he added.

Fortunately, there's currently no evidence that NB.1.8.1 will cause more severe disease. It's still within the JN.1 lineage, which was the dominant variant in winter 2024, though it's not a descendant of LP.8.1; instead, it's more like a "cousin," Lawler said.

Last week, the FDA's Vaccines and Related Biological Products Advisory Committee unanimously recommendedopens in a new tab or window that the next COVID shot should be a monovalent one in the JN.1 lineage. Since companies appear to be choosing a variant that's currently on the wane, what does that mean for the effectiveness of fall COVID boosters?

Probably not much, Lawler said.

"I think trying to get as close to the viruses that are circulating as possible is a very good thing, but there's also the phenomenon that just recency of vaccination is also very important in terms of your protection," he said. "That's been shown over multiple flavors of COVID vaccines now over several years."

"We've been behind for every series of new vaccines and boosters, and we have not been vaccinating with a vaccine that perfectly matches the current circulating strain. Nevertheless, every time we go back and look at the data, the vaccine is protective," he added.

While there's "some extrapolation that you have to do based on now 5 years of accumulated data," Lawler said, it's clear that "every time, these vaccines work."

https://www.medpagetoday.com/infectiousdisease/covid19/115806