CDC Continues to Track the Growth of JN.1

December 22, 2023, 11:00 AM EDT

CDC is posting updates on respiratory viruses every week; for the latest information, please visit CDC Respiratory Virus Updates.

JN.1 continues to increase in proportion

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.

JN.1’s continued growth suggests that the variant is either more transmissible or better at evading our immune systems than other circulating variants. It is too early to know whether or to what extent JN.1 will cause an increase in infections or hospitalizations.

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.

Regardless of JN.1, we are seeing increasing COVID-19 activity this fall and winter season as we have in prior years. COVID-19 activity is elevated and increasing (though not dramatically) in the United States, as measured by emergency department visits, test positivity, wastewater levels, and hospitalizations. It’s a good time to take extra precautions to protect yourself and others, especially while other respiratory diseases including influenza are also on the rise.

Read more about JN.1

Take steps to protect yourself against JN.1 and other circulating variants

The spread of JN.1 does not alter CDC’s COVID-19 recommendations. COVID-19 remains a serious public health threat, especially for people at higher risk of severe disease, such as older adults, infants, and people with certain disabilities and underlying health conditions. We encourage you to take steps to protect yourself and others.

These actions can help protect you and your loved ones against the most severe effects of COVID-19

  • Get your updated COVID-19 vaccine.
  • Test if you develop respiratory symptoms or are exposed to someone who has COVID-19.
  • Talk to a healthcare provider about treatment if you test positive and are at higher risk for severe effects of COVID-19.
  • Help reduce the spread of COVID-19.
    • Improving your indoor air is one of the best ways to prevent spread. This can be as simple as using a portable air cleaner or opening windows (for those with pleasant winter weather). And if your home thermostat offers a FAN option, turn it from AUTO to ON when you have visitors to keep air running continuously.
    • Learn more about other ways to help reduce spread, including testing for COVID-19, wearing masks, and increasing space and distancing.