Coronavirus subvariant JN.1 is growing rapidly in the US, already dominant in the Northeast

CNN
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The US Centers for Disease Control and Prevention calculates that the JN.1 sub-variant of the coronavirus now causes about 20% of new Covid-19 infections in this country and is the fastest-growing strain of the virus. It is already prevalent in the Northeast, where it is estimated to cause about a third of new infections.

JN.1 is descended from BA.2.86, or Pirola, a subvariant that came to the world's attention in the summer because of the large number of changes in its spike proteins: more than 30. Scientists feared that it was so mutated that it would completely escape from the protection of vaccines and antibodies against Covid-19, perhaps triggering another tidal wave of disease as the original Omicron variant did in 2021.

That never happened, but BA.2.86 hung around, developing very slowly in some countries, including the US. Some studies have suggested that it never took off because it may have lost some of its ability to infect our cells.

Enter JN.1, which is two generations removed – a granddaughter, so to speak – of BA.2.86. JN.1 has only one change in its spike protein compared to its ancestor, but this seems to have been enough to make it a fitter and faster virus.

The CDC estimates that the prevalence of JN.1 more than doubled in the US from late November to mid-December. It seems to be helped by holiday travel and weakened immunity.

“When I just look at the growth curve, it's going up pretty steeply and it seems to coincide with the Thanksgiving break in terms of timing,” said Dr. Shishi Luo, head of infectious diseases for genomic sequencing company Helix.

Variant trackers say they expect JN.1 to become the top coronavirus variant worldwide within weeks. The World Health Organization named it a variation of interest on Tuesday due to “rapidly increasing spreadbut noted that the additional risk to public health remains low.

“It's already pretty clear that it's very competitive with the existing XBB variants, and it looks like it's well on its way to becoming the next kind of global dominant variant group,” said Dr. T. Ryan Gregory, an evolutionary biologist at the University of Guelph in Ontario, who has been tracking the evolution of the virus that causes Covid-19.

The mutation in the spike of JN.1 is at a site that Gregory said appears to help the virus escape our immunity.

Studies by researchers at Columbia University and in China indicate that there is about a two-fold reduction in the ability of our antibodies to neutralize this subvariant. While not a huge drop, it could portend another wave of infections on the horizon.

Several countries in Europe – including Denmark, Spain, Belgium, France and the Netherlands – have seen an exponential increase in JN.1 and, with it, increasing hospitalizations. It is also growing rapidly in Australia, Asia and Canada.

This is also happening in the United States, thanks to declining immunity. Too many Americans chose to forgo the latest round of vaccinations for Covid-19 and may as well have passed it last year. As a result, their immunity lacked the important upgrades that help the body fend off the worst effects of Covid-19 infections.

As of Dec. 9, only about 18 percent of adults had received the latest Covid-19 vaccine, about the same low percentage of the population that did last year, according to the CDC.

The CDC urged doctors to work harder to get their patients vaccinated, stressing that it's not too late in the season to benefit from vaccines.

The CDC he also warned that in the last four weeks, hospitalizations for Covid-19 have increased by 51%. With hospitalization rates for flu and RSV also rising, the agency noted that a continued increase could strain hospital capacity.

The good news is that a recent study from the laboratory of Dr. David Ho at Columbia University found that the current Covid-19 vaccine, which was designed to boost the body's ability to fight the XBB family of variants, also offers good protection against BA.2.86 and its offshoots, including JN. 1.

This finding “strongly supports the official recommendation for widespread implementation of updated Covid-19 vaccines to further protect the public,” the study authors wrote.

Last week, the WHO issued a statement supporting the upgraded Covid-19 vaccines against XBB.1.5 because of the broad protection they offer against a variety of variants.

“Fewer people are getting the booster and fewer people are getting Paxlovid,” an antiviral that can reduce the risk of hospitalization and death from Covid-19, said Dr. Alex Greninger, assistant director of the Laboratory of Clinical Virology at the University of Washington. .

“There's been a lot of work to make these vaccines and make these drugs available, so it's very sad when these tools aren't used,” he said.