evidence: CDC has been tracking JN.1 for months, since it first split from its parent, BA.2.86. JN.1 is similar to BA.2.86 but has an additional mutation (L455S) in the spike protein. JN.1 continues to cause an increasing share of infections and is now the most widely circulating variant in the United States. For the two weeks ending on December 23, 2023, JN.1 is expected to account for 39-50% of all SARS-CoV-2 variants. That's an increase from the projected prevalence two weeks ago of 15-29%. We're also seeing an increasing share of infections caused by JN.1 in travelers, wastewater, and most regions around the globe. [...] It's important to know that existing vaccines, tests, and treatments still work well against JN.1, so this variant does not affect CDC's recommendations. Recent laboratory data (here and here) show that the updated 2023-2024 COVID-19 vaccines produce antibodies that protect against JN.1, further indicating that our vaccines work well against this variant. At this time, the spread of JN.1 does not appear to pose additional risks to public health beyond that of other recent variants. CDC is closely monitoring COVID-19 increases domestically and internationally and will communicate if the situation changes.