Coronavirus Subvariant JN.1 Spreading Fast In LA County

A new COVID-19 subvariant is growing fast in Los Angeles County ahead of the winter holidays.

Known as JN.1, it’s the fastest-growing Omicron subvariant in the U.S., causing an estimated 1 in 5 infections nationwide, according to the Centers for Disease Control and Prevention.

It’s already dominant in the Northeast and is spreading rapidly locally, according to the L.A. County Department of Public Health.

JN.1 accounted for 10% of cases in L.A. County in late November, which is the most recent data available. That’s up from just 1% in October.

This week, JN.1 was classified as a “variant of interest” by the World Health Organization because of its “rapidly increasing spread.” It’s been found in many countries around the world, including India, China and multiple European countries.

The WHO says the risk to the public is currently low, and the current vaccines continue to offer protection.

How is JN.1 different?

The virus that causes COVID is constantly changing over time. Omicron has been globally dominant since the winter of 2021. About 30 subvariants of Omicron, including JN.1, are circulating in L.A. County, according to data from the Department of Public Health.

A change in the spike protein of JN.1 seems to help the virus escape our immunity better than other subvariants, said UC Irvine epidemiologist Andrew Noymer.

“When there’s a mutation in the protein, it’s able to evade previous immune responses that we may have developed and become a better infector,” he said. “I expect JN.1 to become the dominant variant, both worldwide and here in California by the end of the winter.”

There are no reports of people becoming more ill with this subvariant than previous ones.

Noymer said the continuation of Omicron is, in some ways, good news because there isn’t likely to be a huge increase in COVID-related deaths, like with previous variants.

“I don’t expect very high levels of mortality because it’s similar enough to viruses we’ve seen before. That isn’t to say there won’t be COVID deaths this winter, but it won’t be catastrophic,” he said.

COVID cases climb

COVID transmission continues to trend upward. L.A. County Public Health is reporting wastewater concentrations of the virus have tripled in the last month. That’s still well below last winter. Public Health is reporting the virus concentration is currently 39% of last winter’s peak.

This week on average 601 people a day were in area hospitals with COVID, which is more than a 65% increase from one month ago. Emergency department visits related to COVID increased last week from 3.6% to 4.6% the month prior.

“We are entering a dense period of gatherings — Christmas parties, people traveling to see grandma, New Year’s Eve parties,” Noymer said. “I think masking and testing is the name of the game.”