JN.1 Covid ‘Variant Of Interest’ Spreading Fast In U.S. — Here’s What To Know

Published 5 months ago
By Forbes | Robert Hart
Netherlands Reimposes Partial Lockdown Amid Latest Covid-19 Wave
(Photo by Pierre Crom/Getty Images)


The World Health Organization said it is tracking a new coronavirus “variant of interest” called JN.1, an offshoot of the highly mutated “Pirola” strain that is spreading rapidly around the world and has become the fastest growing variant in the United States.


JN.1 is an offshoot of the highly mutated omicron variant BA.2.86, often given the nickname “Pirola,” which some experts worried could evade protection from prior infections and vaccination and trigger a large wave of disease like the original omicron variant did when it emerged.

As the WHO already classified BA.2.86 a “variant of interest”—a strain of virus with genetic changes known or believed to affect traits like transmissibility, immune escape and disease severity and that is spreading in a way that could pose “an emerging risk to global public health”—and tracked JN.1 as part of this group, it was already considered to be a “variant of interest” anyway.


The WHO said JN.1 now merits its own standalone classification on account of its “rapidly increasing spread” around the world, adding that it now makes up the “vast majority” of BA.2.86 descendents reported.

The UN agency stressed available evidence, while “limited,” suggests the strain poses a “low” risk to public health.

That assessment was echoed by the Centers for Disease Control and Prevention in early December, when the agency said the JN.1 variant was responsible for between 15% and 29% of Covid cases and was the “fastest-growing variant in the United States.”

Both health agencies said updated booster vaccines will continue to protect against severe disease and death from JN.1, as they do for other variants, and that there is no sign the strain causes more severe disease compared to other variants.


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“The continued growth of JN.1 suggests that it is either more transmissible or better at evading our immune systems,” the CDC said in early December. However, the agency said it’s not clear how much JN.1 is contributing to the recent uptick in Covid activity given patterns of infection normally observed this time of year. It’s also not clear whether JN.1 produces a different set of symptoms to other variants, the CDC said, noting that symptoms “tend to be similar across variants.” Severity and types of symptoms “usually depend more on a person’s immunity and overall health rather than which variant causes the infection,” the agency said. The CDC said it will continue monitoring the situation and that Covid activity is likely to increase over the month of December, urging people to get vaccinated “if you haven’t received one this fall.”


JN.1 is on track to become the dominant variant in the U.S. in a matter of weeks. The agency’s latest projections estimate the variant was responsible for up to 30% of cases as of December 9, up from between 6% and 11% two weeks earlier. It trails dominant variant HV.1, which was responsible for an estimated 27% to 33% of cases as of December 9 and 30% to 34% of cases two weeks before that. In the CDC region covering the Northeast—New Jersey, New York, Puerto Rico and the Virgin Islands—JN.1 is already the dominant variant and responsible for an estimated 32% of cases. The variant is on a steep upward trajectory in other areas as well and is responsible for between 15% and 26% of cases in regions monitored by the CDC.



1,159,864. That’s how many Covid deaths there have been in the U.S. since January 2020, according to CDC data. Since early September, there have been around 1,200 to 1,400 Covid deaths across the country each week, some of the lowest figures since the pandemic began and down from a peak of nearly 26,000 around the start of 2021 when omicron drove a wave of cases.


There is another category that sits above the WHO’s “variant of interest” class that the organization has not used since the emergence of omicron. The “variant of concern” threshold, which would likely secure the variant a Greek letter moniker like alpha, beta or delta, is reserved for strains that pose a significantly increased risk to public health. Such variants would have been shown to be more contagious, cause more severe disease or escape the protection of vaccines and treatments.


The CDC said JN.1 is still closely related to BA.2.86, despite what the differences in name suggest. The difference comes down to how variants are named, the CDC said, and explained that “there is only a single change between JN.1 and BA.2.86 in the spike protein.” The spike protein is an important part of the coronavirus that allows the virus to enter cells and cause infection.


Moderna’s Updated Covid Vaccine Is Effective Against Pirola Variant—As Concern Over New Strain Grows (Forbes)