OTTAWA—Dr. Theresa Tam, Canada’s chief public health officer, now says Canadians can consider wearing non-medical, or homemade masks if they are in situations where they cannot avoid close contact with people, such as on public transit or out buying groceries.

The main thrust of the new advice — which Tam said is not a recommendation — is that it could help prevent an infected individual who shows no symptoms from spreading it to others, not that it will prevent a mask-wearer from getting sick.

The new advice represents a change in Tam’s stance for the general public as the country battles the coronavirus outbreak, and reflects what she said is rapidly changing scientific evidence about the transmission of virus by asymptomatic and “presymptomatic” individuals.

It doesn’t change advice on medical-grade masks, such as N95 respirators, or surgical/procedural masks for health-care workers, who Tam said remain the biggest priority for the supply of masks. “Health care workers need medical masks,” said Tam.

But Tam acknowledged that homemade or cloth masks, even those that don’t require sewing but can easily be cobbled together with a bandana and some elastic bands, could help stop droplets from infected persons from infecting others.

Until now, the federal Public Health Agency of Canada has said that masks worn by the members of the general public who are out and about are not an effective protection against virus transmission.

Tam has repeatedly said that people who wear cloth or homemade masks might have a false sense of security because the masks don’t stop their wearer from getting sick, that they may not wear them properly, or may not remove them safely, and then touch their faces or eyes, causing them to become infected.

But on Monday in a daily briefing, Tam said the special advisory committee to the Public Health Agency of Canada has changed its recommendation, based on changing scientific findings in the past 10 days.

She acknowledged now that wearing a mask can provide “an additional layer” of protection for others, if a person is not yet showing symptoms.

Tam said the new advice is not a recommendation but is a “permissive statement.”

“It depends on the circumstances,” she said, and doesn’t change the main message, repeated daily by public health authorities: that the most effective way to prevent transmission of the disease is through physical distancing, frequent handwashing and disinfecting of commonly touched surfaces.

She defended the agency’s slowness to change its advice.

Tam said that science has evolved quickly in the COVID-19 pandemic, and now there is evidence to show that some infected people are contagious and able to spread the virus within a couple of days before they start showing symptoms. These people are known as “presymptomatic.”

As well, Tam said that some “asymptomatic” individuals — that is, people who have the disease but display no strongly identifiable outward symptoms — are also able to transmit the virus.

Tam stressed the science about asymptomatic transmission is still not clear.

Health Minister Patty Hajdu underscored Tam’s message, adding that social distancing is still the main protection, “but there may be times where you are not able to,” such as taking the bus, or going to a store which isn’t following practices that allow physical distancing.

Tam said medical-grade masks must still be reserved for health-care workers.

She said it remains unknown how big a role asymptomatic people play in driving the pandemic “but we do know it plays a role.”

Loading... Loading... Loading... Loading... Loading... Loading...

Wearing a mask for those people will “lessen the chance your droplets” will infect other people, she said.

Tam said as of Monday morning, the federal tally of COVID-19 cases in the country hit 15,822, with 293 deaths. She said “most concerning are new outbreaks in hospitals and long-term care facilities in several provinces.”

Tam said there are also clear indicators that the disease is hitting young people, and those as young as in their 20s are dying. She said it represents a “serious health threat to everyone,” not just to the elderly or those with underlying health conditions.

To date, Canada has tested more than 339,000 people, with five per cent of them testing positive for COVID-19.

Tam expressed “cautious optimism” saying British Columbia has shown a lower number of cases this week compared to last, and said “this continues to encourage us that collective action can slow the spread.”

But she said it’s important that Canadians do not relax their efforts to cover their coughs, to wash their hands and to practice physically distancing.

“This is no time to relax our preventive measures.”

An hour before Tam made the statement, Prime Minister Justin Trudeau was asked why Canada has been so reluctant to advise the wearing of masks in public, as the U.S. Centers for Disease Control has, and he deferred to Tam, expressing full confidence in her.

“I’m not going to make health recommendations to people. I don’t think politicians should be opining on health solutions or fixes,” said Trudeau.

“I encourage people to continue to listen to her and to health experts and professionals on how best we can keep ourselves safe, how best we can keep our loved ones safe, how best we can keep our health-care workers safe at this time.”

At Queen’s Park, Premier Doug Ford said “it’s a good idea” to wear a non-medical mask when out.

“If you can make them, by all means. But with the (medical) items, we have to make sure the front-line health-care workers get those masks,” said Ford, urging Ontarians not to use medical masks that are urgently needed in hospitals.

“But it was a good point that the chief medical officer of our country mentioned. If you can protect yourself — even a makeshift one at home — I’d do it,” he said.

With files from Robert Benzie