JN.1 COVID-19 variant comprising 21% of new cases

Photo: Marko Geber/Getty Images

The Centers for Disease Control and Prevention is closely monitoring JN.1, currently the fastest-growing COVID-19 variant in the U.S., representing about 21% of new cases, according to the agency's numbers.

The variant is closely related to the prior variant BA.2.86, which was the latest prior to JN.1. It has just one additional change in its spike protein. This small change, the L455S mutation, may make it more apt to evade immune system responses, the CDC said.

JN.1 was first detected in the U.S. in September, and for the first month or so only accounted for 0.1% of coronavirus transmissions. The fact that it has continued to grow, and the rate at which it's growing, suggests that it's either more transmissible or is better at working around people's immune systems. Still, the CDC didn't find evidence that the variant presents an increased risk to public health compared to other current variants.

That's a positive finding not just for patients, but for hospitals, whose resources and workforces were strained almost to the breaking point during the height of the pandemic.

WHAT'S THE IMPACT

Another bit of good news: JN.1 doesn't appear to be more severe than other variants. Updated COVID-19 vaccines are expected to increase protection against it as they do for other variants, and current tests and treatments are likely to still be effective as well.

The current question, according to the CDC, is whether the growth of JN.1 might drive an incremental increase in infections. At this point it's simply too soon to know, especially with cases likely to peak around the new year, as has been the pattern the past few years.

Due to that pattern, COVID-19 activity is likely to ramp up over the next month. The CDC said an updated vaccine is the best way to protect against JN.1 and other variants.

The boosters approved by the Food and Drug Administration in September for emergency use were for vaccines updated by manufacturers ModernaTX Inc. and Pfizer to include a monovalent (single) component that corresponds to the Omicron variant XBB.1.5.

"Regardless of what variants happen, CDC will continue to track them, working closely with partners around the world to understand how they are spreading and how they respond to vaccines and treatments," the CDC said.

THE LARGER TREND

Data from August showed that COVID-19 hospitalizations and deaths were increasing at that time. For the last week of July, the number of hospital admissions in the United States were up 12.5%, for total admissions of 9,056. This compares to about 6,000 people hospitalized during the last week of June, CDC's data showed.

Booster doses have been available since September 2022 for certain age groups and are now available for everyone six months or older. But demand has lagged. In its latest quarterly earnings, Pfizer said it was considering possible cost-cutting measures to manage potential losses from the vaccine, according to Axios.

On May 11, the federal government ended the public health emergency.
 

Twitter: @JELagasse
Email the writer: Jeff.Lagasse@himssmedia.com