Canadian Spin studio followed public health guidelines. But 61 people still had covid-19.

Now, although they appear to have complied with public health regulations, at least 61 people associated with the studio have tested positive for the coronavirus.

“They’ve done all kinds of things to remove the potential for spread,” Richardson told reporters. “Unfortunately, gyms are a risky place due to the fact that generally people take off their masks, they breathe at a higher rate.”

Although Hamilton requires the wearing of masks in most public places, the law includes an exception for anyone “actively participating in a sporting activity or fitness.” In keeping with this policy, studio, SPINCO, allowed riders to remove their masks by simply clipping them onto their bikes, and required them to cover up again before disembarking.

In a recent post on Instagram, Spinko’s owners said they were “hesitant” to reopen after receiving the green light in July and would not resume classes “until it was safe”. Health officials said the studio is temporarily closed and is fully cooperating with the investigation.

“We took all the measures that public health provided, even added a few, and the epidemic is still infecting us again!” Owners wrote. Spinko has more than ten locations across Canada.

As of Tuesday, Richardson said, 44 group-related cases had been detected. An additional 17 “minor cases” were found among the other contacts.

Richardson added on Tuesday that the city will review its gym protocols, but in the meantime, “it looks like it’s like you need to wear that mask” even though government guidelines don’t strictly require it.

“It’s still a good idea to do this, in terms of keeping others safe,” she said.

People should also avoid “classes where you get this type of screaming or music practice”.

She refused to use the term “superspreader” to describe the event but said it was “a very large outbreak”.

“It is alarming that it extends beyond the initial cases that were related to the classroom, but they of course went to their home contacts and other contacts,” she said. “We keep looking at what that means, what do we need to understand about exercise classes?”

Barbara Yaffe, Ontario’s chief medical officer for health, told reporters on Wednesday that the province is reviewing recommendations for spin studios and other gyms in response to the outbreak.

“Even though they followed the instructions, it was clear that there was a major shift, so I think we need to review the guidelines and this is in progress,” said Yaffe.

The outbreak provides additional evidence of the dangers of people gathering indoors without masks, with health experts warning that cases could rise in the coming months as winter weather sets in and it will be difficult to maintain outdoor gatherings and exercise classes.

In August, South Korea confirmed dozens of cases associated with one Starbucks store in Paju City where not many customers wore masks. The store employees, who were wearing masks, were not injured. The outbreak prompted Starbucks to limit its home seats in the country and encourage masks among sponsors.

In other cases, the use of a mask is attributed to preventing a possible outbreak. In May, after a hair salon in Missouri that required masks reopened, two designers – who have worked with more than 100 clients – tested positive for the virus. But masks were in demand in the salon, and of the dozens of clients who chose to undergo testing after their potential exposure, none tested positive.

Amanda Coletta from Toronto contributed to this report.

This report has been updated.