What masks work best against Omicron? Experts are divided, but most say ditch cloth masks

Click to play video: 'Single-cloth masks not effective against Omicron, head of Ontario science table says'
Single-cloth masks not effective against Omicron, head of Ontario science table says
WATCH: The head of Ontario's Science Advisory Table says single-layer cloth face masks may not be enough to protect against the Omicron variant – Dec 17, 2021

Canadians are being urged to ditch certain types of masks in favour of ones experts say will provide more protection against the new, rapidly spreading Omicron variant.

The head of Ontario’s Science Advisory Table, Dr. Peter Juni, said Friday that single-layer cloth face masks may not be enough to protect against Omicron.

“The issue here is if you have a single-layer, the ability to filtrate is absolutely minimal and doesn’t make a difference whatsoever,” said Juni, who pointed to the use of N95 respirators as a more effective option.

The renewed discussion about mask use comes as Canada’s Omicron-driven fifth wave continues to drive daily case counts to record numbers not seen in months, pushing provinces to enact a slew of public health measures and restrictions.

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Juni’s recommendation to ditch single-layer cloth face masks comes amid a call by some public health experts to re-examine masking guidelines, and more actively encourage the use of respirators and medical masks over cloth ones.

Colin Furness, an epidemiologist at the University of Toronto, said public health authorities need to more strongly encourage the use of N95 respirators in indoor public settings.

Furness told the Canadian Press any campaign to push for their use should include resources to help Canadians find respirators that fit best.

“That’s public education we desperately need,” said Furness. “The fact that people are on their own for this is a travesty.”

In November, the Public Health Agency of Canada (PHAC) updated its guidelines on mask use, suggesting respirators such as the N95 are more effective than non-medical masks.

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“In general, while non-medical masks can help prevent the spread of COVID-19, medical masks and respirators provide better protection,” said PHAC on their mask information webpage.

The agency also recommended the use of medical masks or respirators for those in vulnerable at-risk groups, or who run a higher risk of contracting COVID-19 within their work or living situation.

In a press conference Friday, Canada’s Chief Public Health Officer Dr. Theresa Tam also stressed Canadians to follow PHAC’s updated guidance on indoor ventilation and “proper use, construction and fit of face masks.”

While respirators seem to be the consensus among public health experts and officials as the gold standard for protection against Omicron, they are quick to point out the added protection offered by respirators is very much dependent on the masks being properly fitted to a person’s face.

It’s a detail that Dr. Gerald Evans, chair of infectious diseases at Queen’s University, was quick to point out.

“The amount of extra protection you get from an N95 respirator … if it’s not fit-tested, is only marginally better than a medical mask,” said Evans.

While there is an upside to the protection offered by respirators if they are properly fitted, Evans also pointed out the high cost to regularly acquire them, as well as a lack of definitive evidence that N95s prevent transmission in community settings, more so than more cheaply produced medical masks.

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“So there’s no study that shows wearing an N95 statistically or clinically reduces the transmission of COVID 19 — more than a medical mask,” said Evans. “In fact, we have pretty good evidence, medical masks clearly work by reducing the overall infectious dose.”

Click to play video: 'COVID-19: WHO warns of dismissing the Omicron variant as being ‘mild’, calls for stronger measures'
COVID-19: WHO warns of dismissing the Omicron variant as being ‘mild’, calls for stronger measures

In differing guidance towards what looks to be general public use of masks, PHAC said a “respirator worn in the community doesn’t need to have been formally fit-tested as is required in some occupational settings.”

Evans also said the increased transmission of Omicron is not because it’s “more airborne” — a virus’ trait from which a respirator could further protect users. Rather, he said, people with the variant begin shedding higher loads of the virus, due to it replicating rapidly in the cells it infects.

The bottom line from Evans though is: “If you have a lot of money and you can afford an N95 mask or one of those equivalents, go ahead and buy them.”

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“But if you can, get a medical mask — they’re not very expensive … and if you can’t afford that, but you’ve got some good cloth masks, use them, don’t forget to clean them and probably think about double-masking if you think that’s appropriate.”

— With files from The Canadian Press

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