More than five years on from the outset of the COVID-19 pandemic, another new strain of the virus has become the most prevalent in Canada, bringing new symptoms with it.

Here’s what to know:

What is the new COVID variant?

SARS-CoV-2 variant XFG, sometimes called the “stratus” variant, has seen rapid growth since the beginning of this summer, now appearing in the largest proportion of samples in Canada’s federal variant monitoring.

According to Public Health Ontario, XFG is projected to make up a majority of that province’s sequenced tests before the end of September.

The strain’s nickname was reportedly coined by University of Guelph biologist T. Ryan Gregory, who is also credited with dubbing a previously dominant COVID strain “nimbus.” Both names refer to kinds of clouds.

In a June post to X, Gregory notes that while XFG is under the umbrella of COVID-19’s Omicron variant, the same can be said for a great many strains. Omicron has remained the latest Greek-letter distinction for COVID variants since late 2021.

“The reality is that ‘Omicron’ is massively diverse — far, far, far more so than all the other named variants combined,” Gregory wrote.

Even so, he says nimbus and stratus are some of the more distinct subvariants in recent years — the first to garner their own nicknames since 2023.

Unlike many of those before it, the cloud-themed subvariants comparatively “show signs of really taking off and potentially causing a significant increase in infections” over what he says was a comparatively lower level before.

“Reminder: ventilation, air filtration, well-fitting N95 masks, and avoiding high risk exposure (e.g., indoor crowds in poorly ventilated spaces) are variant-proof measures,” his June thread of posts reads.

What are the symptoms?

Anecdotal reports suggest that, on top of typical COVID-19 symptoms, some have found more recent variants to be especially painful.

“The new Nimbus variant of COVID-19 is causing a sharp, ‘razor blade’ type of soreness in the throat,” reads a social media post from Yale University’s medical school. “The reason? The variant replicates in the throat lining, causing cellular damage.”

Health tip: Soothe a ‘Razor Blade’ Sore Throat

The new #Nimbus variant of #COVID-19 is causing a sharp, ‘razor blade’ type of soreness in the throat (pharyngitis). The reason? The variant replicates in the throat lining, causing cellular damage. Try these soothing solutions. pic.twitter.com/EqgxIbpxmJ

— Yale Medicine (@YaleMedicine) June 20, 2025

Over-the-counter lozenges, saline sprays, plenty of fluids and a humidifier may help with discomfort, but the school recommends seeking out a COVID-19 test, and potentially medical attention if circumstances don’t improve.

“You may need to be evaluated for other conditions such as strep throat,” the post concludes.

How serious are the risks?

While it’s always a good idea to practise responsible public health, the risks of the XFG variant haven’t yet proven to be major.

A June report by the World Health Organization notes that the strain is under monitoring, but that initial threat assessments have found the new health risks introduced by XFG to be “low at the global level.”

“Currently approved COVID-19 vaccines are expected to remain effective to this variant against symptomatic and severe disease,” it reads. “Current data do not indicate that this variant leads to more severe illness or deaths than other variants in circulation.”

As for Canada, the latest wastewater monitoring data shows “moderate” COVID-19 activity nationwide, with higher levels in Manitoba, Newfoundland and Labrador.

Just over 1,600 cases of COVID-19 were detected nationally in the first week of September, with 8.5 per cent of tests positive and one hospitalization per 100,000 in the population.