• Posted December 20, 2023

WHO Declares JN.1 a COVID Variant of Interest as It Spreads Widely

The new COVID variant known as JN.1 was named a "variant of interest" by the World Health Organization on Tuesday, which means health officials are now closely tracking its rapid spread across the globe.

So far, the highly mutated variant has not been shown to trigger more severe illness than previous incarnations of the coronavirus. Still, it is spreading faster than its ancestor, the BA.2.86 variant.

"JN.1 continues to be reported in multiple countries, and its prevalence has been rapidly increasing globally and now represents the vast majority of BA.2.86 descendent lineages reported," the WHO wrote in its latest report.

The WHO defines variants of interest as those that are concerning enough to trigger stepped up laboratory studies and field investigations of their spread.

Variants of interest must also have genetic mutations that change a key characteristic of the virus, like its transmissibility or how well it evades treatments and vaccines. The strain must also be growing in a way that it could be "an emerging risk to global public health."

The U.S. Centers for Disease Control and Prevention uses a similar system to classify variants based on their risk to Americans, but the agency has not yet classified JN.1 as a "variant of interest."

However, the WHO said early evidence shows JN.1's mutations do appear to boost its ability to slip past the body's immune defenses.

"Based on its genetic features, JN.1 may possess some antigenic advantage evading previous immunity," the WHO said in its report.

Estimates published by the CDC earlier this month showed JN.1 was the fastest-growing strain in the United States, accounting for more than 1 in 5 cases nationwide. The variant is on track to become dominant nationwide, the CDC has said.

New variant estimates are expected to be published by the CDC on Friday.

Even as JN.1 spreads widely, this season's updated COVID-19 vaccines are still expected to guard against infection from the JN.1variant, the WHO added.

But the WHO has acknowledged early studies of the variant have discovered lower "cross neutralization" in tests designed to mimic the shots' protection.

"[D]espite the reduction in JN.1 neutralization, protection by XBB.1.5 monovalent vaccines are likely to be effective against JN.1," the WHO noted in its report.

More information

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SOURCE: WHO report, Dec. 19, 2023