Right now, all eyes are on the new COVID variant JN.1, a highly mutated new strain that has swept the United States in recent weeks.
JN.1 is now the fastest-growing variant in the country, according to the U.S. Centers for Disease Control and Prevention. It currently accounts for more than a fifth of all infections in the United States
The HV.1 subvariant is currently still the dominant strain – but JN.1 is not far behind. According to the CDC's latest estimates, HV.1 accounted for about 30% of COVID-19 cases in the U.S. in the two-week period ending Dec. 9. JN.1 was the second most common strain, accounting for approximately 21% of cases, followed by EG.5.
Scientists are closely monitoring JN.1, which is a cause for concern due to its rapid growth rate and large number of mutations. However, the new variant is closely related to a strain we have already seen. It is a direct offshoot of BA.2.86, also known as “Pirola”, which has been spreading in the USA since the summer.
JN.1 has one more mutation than its parent strain BA.2.86, which has more than 30 mutations that distinguish it from the Omicron XBB.1.5 variant. XBB.1.5 was the dominant strain for most of 2023 and it is the variant targeted by the updated COVID-19 vaccine, TODAY.com previously reported.
All of the COVID-19 variants currently circulating most widely in the United States are descendants of Omicron, which began circulating in late 2021.
In recent weeks, JN.1 has defeated many other variants, including its parent strain BA.2.86 as well as EG.5 or Eris and XBB.1.16, also known as Arcturus.
As the U.S. enters peak respiratory virus season, some are concerned about whether JN.1 could trigger a surge in COVID-19. Others wonder whether it causes different symptoms and how its mutations might affect tests, treatments and vaccines. Here's what experts know so far about JN.1.
What is JN.1, the new COVID-19 variant?
JN.1 was first discovered in September 2023 and has been detected in at least 12 countries so far, including the United States, according to the CDC. Just like the other newer variants, JN.1 belongs to the Omicron family.
“Think of (the variants) as children and grandchildren of Omicron. “They are part of the same extended family, but they all have their own unique personalities,” says Dr. William Schaffner, professor of infectious diseases at Vanderbilt University Medical Center TODAY.com.
JN.1 is descended from BA.2.86, a sublineage of the Omicron BA.2 variant, as TODAY.com previously reported – this distinguishes JN.1 and BA.2.86 from the other predominant variants such as HV.1 and EG. 5, which descends from Omicron XBB.
“When its parent strain BA.2.86 emerged, everyone was worried because it had a lot of mutations and it looked like it was evading a lot of the immunity from vaccines and the infection population,” says Pekosz. “But (BA.2.86) kind of fizzled out,” Pekosz added.
Laboratory data suggests that Pirola is less contagious and immunocompromising than scientists once feared, NBC News reported.
However, JN.1 discovered an additional mutation in its spike protein, says Pekosz. Spike proteins help the virus attach to human cells and play a critical role in infecting people with SARS-CoV-2, according to the CDC. This mutation could affect the immune escape properties of JN'1, says Pekosz.
“Now it is circulating and growing very quickly compared to other variants and the parent from which it is derived (BA.2.86), says Pekosz.
In early November, JN.1 accounted for less than 1% of COVID-19 cases and now, just a few weeks later, it accounts for over 20% of cases, says Dr. Michael Phillips, chief epidemiologist at NYU Langone Health, TODAY. com.
What are the symptoms of JN.1?
According to the CDC, it is not known whether JN.1 causes different symptoms than other variants.
“At the moment there is no evidence that the JN.1 infection differs from previous COVID variants in terms of disease severity or symptoms, but we are paying close attention,” says Pekosz.
The symptoms of JN.1 appear to be similar to those of other strains, including:
According to the CDC, the type and severity of symptoms a person experiences typically depend more on a person's underlying health and immunity than on the variant that caused the infection.
While there are still serious infections, overall “(COVID-19) causes a lot of milder illnesses,” Schaffner says.
Some doctors have reported that upper respiratory symptoms appear to follow a pattern that begins with a sore throat, followed by congestion and cough, NBC News previously reported.
“The virus adapts. … I think it's getting better and better at infecting people and bypassing pre-existing immunity in the population … but it doesn't change the symptomology too much,” says Pekosz.
There is currently no evidence that JN.1 causes a more severe infection, the experts note.
Is JN.1 more transferable?
“What these (Omicron variants) have in common is that they are highly contagious, and when new variants emerge, they appear to be just as contagious or even more contagious than the previous variants,” Schaffner says.
According to the CDC, the continued growth of JN.1 suggests that the variant is either more transmissible or better able to evade our immune system.
“It is probably a little more transmissible than its parent virus because we have seen an increase in the number of cases that we did not have with (BA.2.86),” says Pekosz. However, it is still too early to say how exactly the transmissibility or immune escape properties of JN.1 compare to other variants such as HV.1, the experts said.
Many of the newer strains, including JN.1, have another mutation that affects how strongly the spike protein binds to cells in the respiratory tract, Pekosz says. “We know that it probably helps the virus reproduce better and evade more of the immune response that is already in place,” he adds.
According to the CDC, JN.1 does not pose an increased public health risk compared to other variants currently circulating.
The changes in JN.1 could give it an advantage over other variants, but it is unclear how this will affect cases in the coming months. So far, “there doesn’t appear to be a massive increase in transmission. … We would be worried if there was a huge increase in cases,” Pekosz said.
Will JN.1 cause a surge?
“At the moment, the percentage of COVID-19 cases caused by JN.1 is increasing, and the total number of cases has also increased slightly,” says Pekosz.
Phillips said test positivity, an early indicator of case numbers, is increasing — the rate rose 11.5% in the past week, according to the CDC. (The CDC no longer tracks the total number of cases in the US).
Hospitalizations have also increased by 13% and intensive care unit admissions by 9% over the past two weeks, according to an NBC News analysis.
“The good news is that we have not seen a significant increase in serious illness or hospitalizations so far and the number of intensive care units is still very low, but we will monitor developments closely,” says Phillips.
The experts note that COVID-19 activity will increase around this time as the country enters the winter and respiratory virus season. According to the CDC, the virus has been increasing in recent years, peaking around New Year's Day.
“At this time, we do not know to what extent JN.1 may contribute to these increases or potential increases through the remainder of December,” the CDC said. Only time will tell whether JN.1 or another variant will cause a surge in infections this winter.
Do COVID-19 tests detect JN.1?
All diagnostic tests for COVID-19 — including rapid antigen tests and PCR tests — are expected to be effective in detecting JN.1 and other variants, according to the CDC.
Testing is an important tool to protect yourself and others from COVID-19, especially before holiday events, Schaffner says.
The symptoms of COVID-19 are often indistinguishable from those caused by other currently circulating viruses, the experts note. These include the respiratory syncytial virus (RSV), the influenza virus and the rhinovirus, which causes colds.
The experts are urging anyone who is sick or exposed to COVID-19 to get tested, especially people at higher risk of serious illness, such as people over 65, who are immunocompromised and have underlying health conditions.
Any American can order four free at-home COVID-19 tests from the government to be delivered by mail via the U.S. Postal Service. To order your free tests, go to COVIDTests.gov.
“Get tested because whether it’s COVID or the flu, we have treatment available,” Schaffner said. Current treatments are also expected to be effective against JN.1, the CDC said.
“JN.1 should be as sensitive to the available antiviral drugs as any other variant,” says Pekosz, adding that antiviral drugs like Paxlovid are most effective when taken within the first few days of infection.
Does the new COVID vaccine protect against JN.1?
The new, updated COVID-19 vaccines, recommended for everyone 6 months and older, are designed to increase protection against JN.1 and other variants, according to the CDC.
Although the shots at Omicron
Data from laboratory studies show that the vaccine appears to produce a strong immune response against the parent strain of JN.1, BA.2.86, Schaffner notes.
The experts emphasize that the new vaccines also protect against severe disease, hospitalizations and deaths. So even if you get COVID-19 after getting vaccinated, the infection will likely be milder and may keep you out of the hospital, Phillips adds.
However, acceptance of the new vaccine among the US population has so far been low, say the experts. According to the latest CDC data on vaccination trends, as of Dec. 8, only about 17% of adults, 7% of children and 36% of adults ages 65 and older have received the new vaccine.
On December 14, CDC officials issued an alert to warn of low vaccination rates against COVID-19, flu and RSV in the United States
Now is the best time to get vaccinated if you haven't already, experts say. “The earlier you get vaccinated, the sooner you are protected and it takes seven to ten days for protection to reach its maximum,” says Schaffner.
Phillips recommends that everyone, especially those at high risk, also get vaccinated against the seasonal flu.
“A vaccination is the best gift you can give yourself and your family this holiday season,” adds Schaffner.
How to protect yourself from JN.1
Every day, but especially during respiratory virus season, people can take steps to protect themselves and others from COVID-19.
The experts encourage everyone:
Stay informed about COVID-19 vaccines.
Test to see if you have symptoms.
Isolate if you have COVID-19.
Avoid contact with sick people.
Improve ventilation.
Wear a mask in crowded indoor spaces.
Wash your hands with soap and water.
This article was originally published on TODAY.com