Canadian mask guidelines have changed. Here’s why you might need an upgrade

Now that cold weather has hit and people are moving indoors, many doctors and scientists are urging Canadians not only to not just wear face masks to protect themselves against COVID-19 – but also to examine closer so this cloth mask keeps you and others as secure as possible.

“In general, while non-medical masks can help prevent the spread of COVID-19, medical masks and respirators offer better protection,” the Public Health Agency of Canada (PHAC) said on its page COVID-19 mask information web, which was updated on November 12.

The updated guidelines also recommend medical masks or respirators for people “who are at risk of illness or more serious consequences from COVID-19” and those “at higher risk of exposure to COVID-19 due to their living situation ”.

Respirators – such as the N-95 and KN-95 masks – are considered the highest level of mask protection and were previously only recommended for healthcare workers who come into direct contact with infectious patients. In these high risk areas, respirators require a “fit test”.

But in a nod to more general use, PHAC guidelines now state: “A respirator worn in the community does not need to have been formally tested, as is required in some professional settings.” .

Responding to a CBC News investigation into why PHAC’s recommendations have changed, the agency said in an email it was “based on the latest scientific evidence on the worrying variants of the SARS-CoV virus. 2, a better understanding of the impacts of vaccination and immunity in the population and new data available on the types of masks and their effectiveness. “

In addition to the updated online guidelines, Dr. Theresa Tam, Canada’s Chief Public Health Officer, recently posted a series of tweets illustrating how COVID-19 could be spread through the air, using the analogy second-hand smoke.

Many doctors, scientists and engineers say this shift in message reflects a growing body of evidence to suggest that COVID-19 is spread largely through aerosols (tiny particles that can hang in the air), and not just through aerosols. respiratory droplets (larger particles) transmitted by close contact with an infected person.

In turn, that means it’s important to re-evaluate the masks we use, they say.

“This marks a transition in Canada towards a recognition of the importance of aerosol transmission through the air in the transmission of this virus,” said Dr. Brooks Fallis, intensive care physician with the William Osler Health System in the Greater Montreal area. Toronto.

Because aerosol particles are smaller and can build up in the air over time, Fallis said, the best performing masks are essential if you’re going to be indoors with other people for a long time. time.

Some doctors recommend wearing a respirator, such as this N-95 mask, if you are in a closed indoor space with other people for a significant period of time. (Adrian Wyld / The Canadian Press)

“If you’re just, you know, walking into the grocery store to grab a few items, or if you’re… walking down a crowded street and want to wear a mask, then that’s fine. [to wear a medical mask]”said Fallis.

“But if you are in an enclosed space with a lot of people, then we should upgrade to higher level masks, like the KN-95 masks or a respirator type mask, which offers better fit and better filtration.”

Masks are important even when you’re fully vaccinated, say PHAC and doctors, because although it’s much less likely, infection with the virus that causes COVID-19 – especially the highly transmissible delta variant – can still happen.

Better availability of higher quality masks

Another big factor that has changed since the start of the pandemic, experts say, is the availability of medical / surgical masks and respirators.

“There has been a lot of controversy over the N-95 masks because there weren’t enough for healthcare workers. The message, then, quite understandable, was: “Keep them for the healthcare workers and we will use other alternatives.” , ‘”Said Marianne Levitsky, industrial hygienist at the Dalla Lana School of Public Health at the University of Toronto.

“But things have changed a lot. We now have Canadian manufacturers making N-95 type masks and they are much more widely available than before,” she said.

WATCH | Respirators are considered the highest level of mask protection:

Should N-95s become the new mask standard?

With growing concern about the spread of COVID-19 aerosols, new guidelines suggest N-95s should be worn in high-risk situations, but experts say cloth masks still have their place and new ones manufacturing standards improve quality. 1:59

Why your masks might not be as protective as you think

With the increase in contagious variants of COVID-19, there is more and more talk of improving people’s masks. The type of mask is important, but as Andrew Chang of The National found out, so is the fit. 4:47

Experts agree that any mask is better than no mask, as it will capture droplets and aerosols from the wearer’s nose and mouth and protect others. But there is growing evidence that a better quality mask can also offer some protection to the wearer.

“Masks or respirators, they control in two ways. First, they can prevent an infected person from emitting these infectious aerosols into a space, and they can also protect the wearer from inhaling them,” Levitsky said.

Conor Ruzycki, who studies aerosol science and technology at the University of Alberta, says respirators, like the Canadian-made one he wears, offer better protection against aerosol transmission of COVID-19. (SRC)

“Cloth masks were always sort of something that was going to save us time as we moved towards something better,” said Conor Ruzycki, a PhD student in mechanical engineering at the University of Alberta studying aerosol science and technology.

“Now that we understand this disease better, we know that these little aerosols play a bigger role; we should be moving towards… using better mask materials.”

The 3 Fs of choosing a mask

There are three F words to keep in mind when assessing how well a mask will protect you and others: fit, filtration, and function (also known as breathability).

“Adjustment is critical in determining the efficiency of filtration in a real environment,” said Ravi Selvaganapathy, professor of biomedical engineering at the Center of Excellence for Protective Equipment and Materials at McMaster University.

“You can have the best quality material, but if it doesn’t fit your face, then most of the air goes through those large spaces that are there and not through the filter material.”

The filter material for medical / surgical masks and N-95 respirators is actually the same, but the respirators hug a person’s face better, Selvaganapathy said.

A “knot-and-fold” fit can improve the fit of disposable masks – including medical masks, the Centers for Disease Control and Prevention (CDC) advise.

“Tie the earrings of a three-ply face mask where they meet the edge of the mask,” the CDC website says. “[Then] fold and slide unnecessary material under the edges. ”

Cloth masks often offer good fit and function (breathability), but the quality of their virus particle filtering is usually a wild card, experts say, as they are made of various materials and are unregulated.

“There are no standards. When you buy a cloth mask, it usually doesn’t tell you what the filtration is,” Levitsky said. They can protect 20 to 80 percent, she said. “So she is a great unknown.”

The filtration of medical / surgical masks and respirators is classified by the standards body ASTM International. And some non-cloth, non-medical masks available in stores may look like medical masks – but aren’t, experts say, so it’s important for consumers to check the label.

Medical / surgical masks are classified by ASTM International. Experts warn that some disposable non-medical masks look the same but are not certified. (CBC / Radio-Canada)

The ASTM has started a voluntary certification program for non-medical masks, but at this point there aren’t many certified non-medical masks available.

In an effort to better curb the transmission of COVID-19, some countries, such as Germany and Austria, have made medical-grade masks and respirators mandatory instead of cloth masks in public spaces.

In many cases, they’ve been given away free or subsidized, Fallis said – a move he would like to see Canada make.

“I think it’s a profitable investment because it’s another way to bring down business [and] to make better quality masks a little cheaper, especially for people … [for whom] it’s a financial burden to buy masks, ”he said.


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