Covid JN.1 Variant Is Driving Nearly Half of Cases: What to Know, Including Symptoms

The Centers for Disease Control and Prevention said the variant’s speedy spread suggests it is either more transmissible than other circulating variants or better at evading our immune systems. But existing vaccines, treatments and tests still work against it, the CDC said.

Here is what we know about the new variant:

What is the JN.1 Covid-19 variant?

JN.1 emerged in August, according to the WHO, and is an offshoot of the original Omicron variant. It is a descendant of the variant BA.2.86, nicknamed “Pirola,” which caused some concern among scientists but didn’t end up taking off.

Compared with BA.2.86, JN.1 has a single mutation difference in the spike protein, the WHO said.

“It looks like the mutation in the spike protein probably gives it some advantage,” said Emily Smith, an epidemiologist and infectious-disease expert at George Washington University’s Milken Institute School of Public Health.

How widespread is JN.1?

JN.1 has been spotted in 41 countries including the U.S. as of Dec. 16, the WHO said. It accounted for 27% of global virus sequences as of Dec. 3, and the countries reporting the highest portions of cases are France, the U.S., Singapore, Canada, the U.K. and Sweden.

In the U.S., JN.1 made up 44% of cases as of Dec. 23, according to estimates from the CDC. That is up from roughly 21% two weeks before. It is the most-common variant in the U.S. Nearly all variants circulating, including JN.1, are Omicron subvariants.

What are the symptoms of the new variant?

New symptoms haven’t been reported with the variant, so the main symptoms to look for are still the same: cough, fever or chills, body aches, congestion, loss of smell and taste, sore throat and fatigue.

How dangerous is the new JN.1 variant?

The CDC said on Dec. 8 that there is no indication JN.1 causes more severe disease than other circulating variants.

The WHO said the additional public-health risk that JN.1 presents is low globally. But Covid-19 and other circulating pathogens could exacerbate the burden of respiratory disease, the WHO said. For most people, Covid-19 still poses the biggest risk for getting seriously ill compared with the flu or RSV.

“Things are circulating seasonally in a way that feels more in line with years past,” Smith said. “Covid is still one of the more serious bugs when we compare it to some of the others.”

Do Covid-19 vaccines work against JN.1?

Yes,  preliminary research shows that the latest Covid-19 vaccines produce a robust immune response against JN.1.

The WHO said current population immune defenses and the updated vaccines should be cross-reactive against JN.1. The variant’s ability to escape immune responses depends on the background immunity in each country, the organization said.

Vaccine makers Pfizer, Moderna and Novavax have said their updated Covid-19 shots generate immune responses against JN.1’s close parent, BA.2.86.

“Data shows that all of the antibodies are a really good fit, luckily, for JN.1,” said Jeremy Kamil, a virologist at Louisiana State University Health Shreveport. “That’s really good news.”

Kamil pointed out that Covid-19 vaccine uptake has been low this season, some 18% of adults having gotten a shot as of Dec. 15, according to the CDC. Some 42% of adults have gotten their flu shot this year and 17% of people 60 and older have gotten an RSV vaccine.

Previous infection and vaccination significantly reduce your risk of severe disease, hospitalization and death, but they don’t guarantee you won’t get sick again, virologists said.

Covid-19 is constantly evolving and finding ways to evade our immune system. The antibodies produced in response to an earlier infection or vaccination might not be as effective at staving off a new variant, Kamil said. They also wane over time.

Staying up to date on Covid-19 booster shots can help increase protection against newer variants. For the recently sick, virologists recommended waiting six months after infection to get a booster.

“If you get boosted once a year, you’re in a much better position to resist infection,” Kamil said.

Are Covid-19 cases rising in the U.S.? How does this season compare with last year?

Yes, Covid-19 cases and hospitalizations are increasing in the U.S., with some 26,000 new Covid-related hospital admissions the week ending Dec. 16, according to the CDC.

Covid-19 hospital-admission rates are significantly higher for people 70 and older, CDC data show. There were fewer Covid-19 hospital admissions in the last week compared with the same time last year. The CDC said in late November that it anticipated hospitalizations from respiratory diseases this fall and winter to be similar to last season.

Are flu and RSV cases increasing right now, too?

Yes, other viruses and pathogens including flu and RSV are spreading alongside Covid-19. RSV infections have been increasing for weeks but appear to be peaking in parts of the U.S., CDC data show.

The CDC estimates that at least 7.1 million people have been sickened with the flu this season, including some 73,000 hospitalizations and 4,500 deaths. Flu activity remains elevated and increasing in most of the country.

What Covid-19 precautions should I take during the holidays?

Health officials are urging people to get vaccinated for Covid-19, flu and RSV, if eligible. The shots take about two weeks to provide full protection.

Wearing a mask in crowded places, washing hands, covering coughs and sneezes, and providing good ventilation all help, doctors said. People should take a test if they feel sick and stay home, and people with Covid-19 or the flu at risk of getting seriously ill should seek treatment.

“If people know they’re sick with a cough, a sore throat or runny nose, stay home,” said Dr. Steven Stack, Kentucky’s health commissioner and president of the Association of State and Territorial Health Officials. “You’ll miss the gathering, but you won’t get everyone sick.”