CDC calls COVID-19 variant JN.1 'fastest-growing' strain in U.S.

Dec. 19 (UPI) -- The U.S. Centers for Disease Control and Prevention estimates that the COVID-19 variant JN.1, which is a descendant of this summer's BA.2.86, is currently the fastest-growing variant in the United States.

JN.1 accounts for about 21% of all new COVID-19 infections and is already dominant in the Northeast, where it accounts for an estimated 32% of new cases.

"Amid the peak of respiratory virus season in the U.S., a highly mutated form of SARS-CoV-2 is spreading and contributing to rising cases nationwide: JN.1," the American Medical Association said in a statement Tuesday.

JN.1, which first emerged in September, has gained steam during the holiday season.

"JN.1 accounts for more than 20% of all cases in the U.S. and could be more transmissible and better at slipping past people's immune systems," the AMA added.

The symptoms of JN.1 are similar to other COVID-19 variants and subvariants, which include cough, sore throat, congestion, runny nose, sneezing, fatigue, headache, muscle aches and altered sense of smell.

The CDC and the AMA both recommend the best protection is to remain up-to-date with COVID-19 vaccinations, wear a medical-grade face mask in crowded spaces and practice good handwashing.

"At this time, the expected public health risk of JN.1 and BA.2.86 variants, according to the CDC, remains low for severe illness compared with other variants," the AMA said. "But during the winter and holiday season, there are more opportunities for the virus to spread as it has during the last couple of years."

The CDC estimates JN.1 more than doubled in the United States between Thanksgiving and mid-December, due to added holiday travel and waning immunity.

"When I just look at the growth curve, it is rising quite sharply, and it seems to coincide with the Thanksgiving break in terms of timing," said Dr. Shishi Luo, head of infectious diseases for the genomic sequencing company Helix.

The World Health Organization is also tracking the variant, stating Tuesday that JN.1 could become the leading coronavirus variant in the world by January.

"Due to its rapidly increasing spread, WHO is classifying the variant JN.1 as a separate variant of interest from the parent lineage BA.2.86," the World Health Organization wrote Tuesday in a post on X, formerly Twitter.

"The additional global public health risk posed by JN.1 is currently evaluated as low. Despite this, with the onset of winter in the Northern Hemisphere, JN.1 could increase the burden of respiratory infections in many countries."