We still don't know exactly how it started — a runner on a treadmill, or perhaps someone lifting weights — but an outbreak at a gym in Quebec City has become one of the largest recorded COVID-19 superspreading events in Canada. The Méga Fitness Gym, tucked behind a busy highway in an industrial section of the provincial capital, became a major source of contagion for the B117 variant first identified in the United Kingdom, which now accounts for 70 per cent of all cases in Quebec City. The gym was shut down March 31 as the city was once again put under lockdown. To date, there have been 222 people infected at the gym, another 356 related cases involving outbreaks at 49 workplaces and a 40-year-old man has died. But officials have yet to provide key details on the outbreak that can help inform the public, including whether it was sparked by the more contagious and potentially more deadly variant and whether it was driven by aerosol transmission — or microscopic airborne particles. The outbreak is now the subject of an epidemiological investigation but some of the specifics of how the virus spread are being kept confidential, said Mathieu Boivin, a spokesperson for the local health authority. The health authority says the gym was in violation of at least three public health orders before it was shut down. Gym staff reportedly didn't ask patrons if they were suffering from symptoms of COVID-19, clients weren't kept two metres apart and employees weren't wearing the required personal protective equipment. The gym's owner, Dan Marino, has not responded to requests for comment. In a Facebook post, he defended his efforts to follow public health regulations. Dr. Isabelle Bertrand, an emergency room physician at Quebec City's Hôpital Saint-François d'Assise, began to see the direct consequences of the outbreak earlier this month. One of her patients was a man who contracted the virus from his son, who got it while working out at the gym. Some hard-hit regions of Quebec still allow for indoor fitness classes across Canada, or did up until recently, despite the known increased risk of transmission from variants of the coronavirus. (Ivanoh Demers/Radio-Canada) Now, she said, it's more difficult to know how her patients contracted the virus, as it spreads more widely in the community at a quickening pace she likened to a "pyramid scheme." Bertrand said her ER just keeps "getting busier and busier." "We're close to a point where we're really getting concerned again," she said. A 'stunning' outbreak and more transmissible variants The outbreak isn't the only reason Quebec City for the recent spike in cases, but health experts say it was a key driver. Raymond Tellier, an infectious diseases specialist, medical microbiologist and associate medical professor at McGill University, called the outbreak "stunning." "This is the kind of setting where if you don't have proper ventilation and if you have too much crowding, you could indeed have a superspreading event linked to aerosol," he said. "This one is remarkable." It's also not the first major outbreak of its kind tied to a fitness centre in Canada. Another superspreading event at a downtown Hamilton, Ont., spin studio in October led to at least 85 people being infected with COVID-19. Similar to the Quebec City outbreak, Hamilton's Spinco saw 54 people infected with COVID-19 in the studio who then went on to infect 31 others in households, schools, daycare centres, healthcare facilities and other workplaces. Another outbreak at Spinco, a spinning studio in Hamilton,Ont., infected dozens of people in October 2020.(Bobby Hristova/CBC) In the U.S., the Centers for Disease Control and Prevention published a study on an outbreak at a gym in Chicago in August that saw 55 people infected among 81 attendees. Masks were worn infrequently during exercise by patrons — some of whom had COVID-19 symptoms. The difference between these outbreaks and the one in Quebec City though is that the more transmissible variants of the coronavirus weren't circulating widely in the community at the time like they are now. A year later, policies still lag behind the science Prof. Linsey Marr, an expert on the airborne transmission of viruses at Virginia Tech, said it's surprising that these types of outbreaks are still happening a year into the pandemic, given the growing body of research on aerosol transmission driving superspreading events. She said the Quebec City outbreak had all the hallmarks of a "classic" superspreading event: a crowded indoor space, poor mask adherence and exercise activities that lead to heavy breathing and increase the risk of aerosol transmission. We can't expect the public to follow all the latest science ... if they see that the gym is open, they're going to assume that it's safe. - Prof. Linsey Marr, expert in airbone viruses at Virginia Tech "We can't expect the public to follow all the latest science and so they're going to go about their lives based on probably what's open or not," she said. "And if they see that the gym is open, they're going to assume that it's safe." Marr said the situation also underscores how public policy has failed to evolve to reflect the scientific evidence that COVID-19 spreads primarily through the air rather than surfaces. "People tend to latch on to the first thing they hear, which was to wipe down your groceries, a year ago," said Marr. "But I think we need really a campaign to just clarify to people kind of how the virus is transmitting and then policies that match that." WATCH | Quebec City's COVID-19 surge leads to more restrictions: Gyms have since been ordered closed in Quebec City. They were also closed last week in Montreal and Laval as part of restrictions aimed at preventing the kind of surge already underway in the capital. But some hard-hit regions still allow for indoor fitness classes across Canada, or did up until recently, despite the known increased risk of transmission from variants. Manitoba moved to reopen gyms and indoor fitness classes in early February, the same day it recorded its first case of B117, and has so far allowed them to remain open despite being at the beginning of a third wave of the pandemic. Alberta reopened gyms in late January despite a rapid rise in variant cases, but announced last week the province would return to Step 1 restrictions, which included closing them. B.C. allowed for indoor fitness with masks required only when not working out up until the end of March, when it implemented a three-week "circuit breaker"-style lockdown that saw gyms closed but one-on-one fitness classes permitted. WATCH | Inside some of Canada's hardest hit hospitals in the 3rd wave of COVID-19: "There is pandemic fatigue at a time where the variants are coming in, and also too much anticipation of vaccination," said Tellier. "We must not lower our guard too soon and that's what's happening right now." Tellier said the recent rapid change in public health restrictions in Canada's hardest hit regions is in direct response to the spread of variants — but it remains to be seen if those measures will have an impact. "Governments thought they could open up a bit, which is very much what people wanted too, but it's not working," he said. "Over the next two to three months we need to be resigned to the fact that life is not coming back to normal just yet and we need to be really careful — even more so than before because of the greater transmissibility of these variants. This is unfortunate, but this is what it is."