COVID-19 subvariant JN.1 is now dominant in Canada: What you should know about the strain as it spreads

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The new COVID-19 subvariant, JN.1, has become the new dominant strain across Canada, according to the latest data, which indicated it currently makes up more than half of all infections.

According to the Public Health Agency of Canada's (PHAC) most recent update on Jan. 3, the subvariant accounts for 51.9 per cent of all reported COVID-19 cases in the country. HV.1, which was the last subvariant spreading across Canada, fell to 18.3 per cent of cases in the latest figures.

Since first being detected in Canada on Oct. 9, according to Global News, JN.1 has been quickly growing, especially in December.

In the beginning of that month, HV.1 was still the dominant strain, but JN.1 cases grew from making 16.4 per cent of all cases on Dec. 3, to 26.6 per cent by Dec. 10. A week later, JN.1 made up the highest percentage of all subvariants at 38.5 per cent, where HV.1 eventually fell to 24.4 per cent.

The World Health Organization classified JN.1 as a "variant of interest" on Dec. 19, but noted evidence showed its risk is low. The PHAC then named it a variant of interest in Canada on Dec. 21.

But how does JN.1 differ from the other COVID-19 variants also circulating, and is it something you should worry about? Read on to learn more.

What is the JN.1 COVID variant, and how is it different from other strains?

JN.1 is considered an "offspring" of the strain BA.2.86 in Canada, which has been spreading since summer 2023. They're both descendants of Omicron and, according to the Centers for Disease Control and Prevention (CDC), nearly identical.

The only difference between JN.1 and BA.2.86 is a single spike protein, which helps the virus better invade human cells.

Dr. Zain Chagla recently told Yahoo Canada this may help JN.1 better at receptor binding and have better antibody evasiveness. The infectious disease physician and head of infectious disease services at St. Joseph’s Health Care in Hamilton, Ont. added this can lead to the strain's ability to "cause an impact in terms of spread or the ability to infect populations."

Is JN.1 more contagious than previous COVID strains?

There is currently no evidence that JN.1 causes more severe infections of COVID-19 than other strains. However, the fact it accounts for a majority of COVID-19 cases in several countries and continues to rapidly grow suggests it might be more contagious.

"Hypothetically, this may be because it's better at getting past the bodies' immune defenses," Chagla shared. "For it to become dominant means it's spreading faster than other variants that are currently out there in the background."

Will JN.1 impact hospitals in Canada?

JN.1 likely won't lead to a mass hospitalizations in Canada. However, this is also the time of year where viruses like RSV and influenza are also circulating.

"I don't think we're going to see a massive destabilization in Canada, but I will say that things in health care are already tight at this time of year due to other respiratory viruses," Chagla noted.

"Even though it's not likely to lead to surges like we saw in 2021 and 2022, it's not going to be comfortable to have around and there are still going to be impacts on the health-care system regardless."

That could include health-care workers getting infected, leading to staff shortages that may overwhelm an already-strained system, he added.

What are the symptoms of JN.1? Are they more severe than other variants?

According to the CDC, there isn’t evidence JN.1 causes more severe symptoms than other strains of COVID-19 we’ve dealt with before.

"Most of the severity, the early markers, aren't seeing any difference in terms of symptoms," Chagla shared.

"While there doesn't seem to be a difference in symptom profile, an increase in numbers does mean you're going to have a small number of those people with adverse outcomes. More cases does, unfortunately, mean more severe disease."

Chagla also said to bear in mind the symptoms of JN.1 are very hard to distinguish among not just other strains of COVID, but even among the other respiratory viruses circulating right now.

JN.1 symptoms include:

• Loss of sense of taste or smell

• Congestion

• Fatigue

• Headache

• Fever or chills

• Cough

• Runny nose

• Sore throat

The CDC noted the severity of symptoms you experience depends on your overall immunity and whether you already have any underlying medical conditions.

"We tend to see older adults, people with medical conditions being the ones hospitalized," Chagla said, adding people who live in crowded, enclosed spaces — like shelters or long-term care facilities — will also be more at risk of infection and disruption of these services.

Do rapid tests work on JN.1?

Chagla said while molecular tests are functioning fine, if you're using rapid tests, you'll need to be more cautious.

"As more immunity comes into the population, people are getting re-infections and the rapid tests are now often negative on the day of symptom onset," he explained. "In 2020 and 2021 when people weren't particularly immune to the virus, the rapid tests would be positive on the day of symptoms, but they’re often not accurate anymore."

If you're using rapid tests, he said to make sure you test multiple times over a two or three-day period after your symptoms start to really rule out COVID.

How can you protect yourself from the JN.1 COVID-19 variant?

"The same tools still apply to help minimize the spread of JN.1," said Chagla, referring to masking in crowded spaces and staying up to date with your vaccines.

The latest COVID-19 booster was designed for the XBB.1.5 variant, but Chagla noted the mentality that a booster that's designed for one variant won't work on another isn't accurate.

"We set it to what's predominate at the time, but the reality is these vaccines broaden the immune system response," he said, noting new lab studies that show people with the latest vaccine make antibodies that offer "reasonable protection" against the new JN.1 variant.

"Because it is a surge, especially for those who are high risk, having access to testing, staying home when sick and accessing treatment are the best protocols to follow."

And since there are so many other respiratory viruses circulating this holiday season, Chagla suggested staying home if you experience symptoms, regardless of whether or not you have a positive COVID-19 test.

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