It has 2 mutations which have not been seen together in any previous variant. These mutations may allow it to infect more people and may also allow it to evade our immune system (immune escape), which means antibodies created after vaccination or prior infection may not protect a person from getting infected

Dieter Rams

The World Health Organization (WHO) has declared it a “variant of interest.” There is no evidence that JN.1 causes more severe disease, the CDC says, but its rapid spread suggests it is either more transmissible or better at evading the immune system than other circulating variants.31 Jan 2024

3 Things to Know About JN.1, the New Coronavirus Strain

As cold winter weather drives people indoors and flu, colds, and other seasonal respiratory viruses circulate, SARS-CoV-2, the coronavirus that causes COVID-19, has continued to mutate and spread. Most recently a strain called JN.1 moved swiftly to become the most widely circulating variant in the United States, accounting for an estimated 83% to 88% of all circulating variants toward the end of January.

While it can be difficult, if not impossible, to predict the evolution of the coronavirus and its descendants, the Centers for Disease Control and Prevention (CDC) projects that JN.1 cases will continue to rise through the winter. The World Health Organization (WHO) has declared it a “variant of interest.” There is no evidence that JN.1 causes more severe disease, the CDC says, but its rapid spread suggests it is either more transmissible or better at evading the immune system than other circulating variants.

Where did JN.1 come from, and how is it different?

The JN.1 strain surfaced in the U.S. in September. It is a close relative of BA.2.86 (informally referred to as “Pirola”), a lineage of the Omicron variant that the CDC has been tracking since August. (While the Omicron variant, which first took hold in the U.S. in 2021, has had multiple descendants, the original strain is no longer in circulation.)

A difference between BA.2.86 and JN.1 is that the latter has one mutation in its spike protein, a single change that may or may not alter any of the traits that characterize the virus, although preliminary research shows that it may provide extra immune evasion.