Mask myths, debunked: No, wearing a mask won't 'shut down' your immune system

WATCH: Busting COVID-19 mask myths

In an attempt to help keep the number of novel coronavirus cases in Canada low, masks are officially required by law in several regions across Canada.

In Toronto, a bylaw that requires masks to be worn in all indoor public places takes effect July 7. The city already requires people to wear masks on public transit.

The Quebec government announced on Tuesday that masks will soon be mandatory on public transit. Public transit authorities in the Greater Montreal area — the epicentre of the COVID-19 outbreak in Canada — have been handing out masks to commuters.

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In early June, Montreal suburb Côte Saint-Luc passed a bylaw that makes wearing a mask mandatory in indoor public spaces such as stores and municipal buildings as of July 1.

Countries that quickly resorted to widespread mask-wearing had far lower death rates and shorter COVID-19 outbreaks, according to a recent study, suggesting that masks worn by ordinary people may be helpful in curbing the spread of the virus.

However, some Canadians still worry about possible negative health implications associated with wearing a mask — even though there is no evidence to support any of these claims. Misinformation floating around online about the science around masks has compounded this issue.

One graphic with false information on the danger of masks has been shared on multiple accounts across various social media platforms, and doctors are worried such claims will lead people not to wear a mask amid the COVID-19 outbreak.

Several doctors, surgeons, nurses and other trained health professionals have taken to social media to debunk such myths and beg people to wear masks whenever possible.

“Your average individual who is not having any acute issues or any chronic issues with their lungs … should be totally fine (wearing a mask),” said Dr. Alon Vaisman, an infectious diseases and infectious control physician at the University Health Network in Toronto.

“Surgeons wear masks for very long periods of time … Nurses do the same thing without having any issues with oxygen.”

Below, two Canadian doctors debunk some of the claims made about masks in these misleading social media posts.

‘Masks decrease oxygen intake’

One of the claims circulating about masks is that they limit your body’s oxygen intake. Vaisman says this is largely false unless you have a pre-existing respiratory condition.

“If your oxygenation is poor to begin with, adding something on top of your face will make it more challenging (to breathe) and you may have more difficulty … but this is a small number of individuals, generally speaking,” he said.

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Dr. Matthew Cheng, a microbiologist at the McGill University Health Centre, agrees.

“We know that this is absolutely false,” Cheng said.

“There are thousands of operating staff, including surgeons, nurses, psychotherapists, anesthetists … all of them, who wear masks for prolonged periods of time and are able to operate safely on patients without any deleterious effects, (nor) any decrease in oxygen intake.”

‘Masks increase toxin inhalation’

If your concern is inhaling toxins from the materials used to make masks, don’t worry — it’s the same material as your clothing, Vaisman said.

“The material (both medical and homemade) masks are made of aren’t toxic at all … they’re just a fabric or some kind of polymer that’s really no different than your clothing,” he said.

Toxins in the air shouldn’t be of concern, either.

“As for toxins in the air, there’s no difference when you’re breathing (without a mask),” Vaisman said.

In fact, it’s more likely that your mask is keeping toxins out.

“The particle filtration efficiency of masks is somewhere around 90 per cent, and if it’s a cloth mask, it’s between 20 and 60 per cent,” he said.

“The point is that you’re only potentially decreasing your ‘toxin inhalation’ — not increasing.”

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The only toxin that would be of any concern for health experts is carbon dioxide (which we expel when we exhale), but you don’t inhale carbon dioxide when you wear a mask.

“Masks are not a closed system. When you exhale, the (carbon dioxide) is gone,” Vaisman said.

‘Masks shut down the immune system’

Vaisman thinks this claim follows in line with the hygiene hypothesis, which purports that “if you don’t expose yourself to germs, your immune system won’t be trained to deal with them,” he said.

“That’s exactly the thing we’re trying to prevent here (with COVID-19).”

Basically, when you receive a vaccine for something like influenza, you get a small dose or a “dead version” of the pathogen, Vaisman said.

That’s how your body builds up a defence against the pathogen. However, there’s no dose of COVID-19 that doctors consider to be safe, Vaisman said.

“You’re not shutting down your immune system by preventing this (exposure) — you’re protecting it.”

‘Masks increase virus risk’

The above Instagram post claims that wearing a mask encourages “triggering and infection from dormant retro viruses already in the body.”

However, COVID-19 is a type of virus that is “incapable of having a dormant state,” Cheng said. “It’s therefore incapable of ‘reactivating’ whether you wear a mask or not.”

Even viruses that are able to lay dormant in humans “do not reactivate by wearing a mask,” he said.

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Vaisman agrees.

“The more you protect yourself from viruses entering your body, the better,” he said.

“There’s no benefit in breathing in a respiratory virus. That’s the bottom line.”

‘Masks are scientifically inaccurate’

In the above Instagram post, the claim is made that “virologists measure COVID-19 to be 80 to 140nm in size, making the weave of material masks to be the equivalent of a chain-link fence to a mosquito.”

However, this gravely misrepresents how COVID-19 actually spreads, Vaisman said.

“Clearly the virus itself is quite tiny … but the COVID-19 is carried in a droplet, that’s how it moves through the air,” he said. “It’s essentially like a tiny drop of water, which you can block with a mask.”

Cheng agrees: “The mask doesn’t serve to block the virus moving in and out; the mask serves to reduce the droplets which carry the virus,” he said.

“We know that masks are very good at preventing droplet spread of a respiratory infection.”

He says people need to keep in mind that masks aren’t simply for protecting the individual wearing it, but to reduce the amount of virus a person can shed.

“You’re wearing a mask as much to protect yourself as to protect the individuals around you,” Cheng said.

‘There aren’t any peer-reviewed studies on mask effectiveness’

There are few robust, peer-reviewed studies about the efficacy of mask-wearing in public during the COVID-19 outbreak because the pandemic has only just started.

However, there is ample peer-reviewed data about the efficacy of mask-wearing in a medical setting that shows it’s “absolutely beneficial,” Vaisman said.

“It’s sufficient to extrapolate from medical settings the benefit of a mask. If health-care workers are wearing (one) during high-intensity exposure with a patient, then it should confer a similar level of benefits to the general public.”

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Wear a mask

Both Vaisman and Cheng overwhelmingly support the recommendation that Canadians wear a mask in any enclosed space where physical distancing cannot be practiced.

“If you have a sick individual, especially within less than six feet of you, who’s coughing or sneezing, the droplets that are generated … can be protected against if you wear a mask — particularly if that individual wears a mask, too,” Vaisman said.

“There’s very little risk associated with it. It’s mostly just the inconvenience and the costs associated with a mask, but there are potentially a lot of benefits.”

The real benefit of mask-wearing will only come once most people are wearing them, Cheng said.

“We’re not only protecting the individuals who are wearing the mask, but also protecting against transmitting the virus to others,” he said.

“That’s why, as the community comes together, then we’ll be able to really help mitigate the havoc that (the novel coronavirus) has caused.”

Questions about COVID-19? Here are some things you need to know:

Symptoms can include fever, cough and difficulty breathing — very similar to a cold or flu. Some people can develop a more severe illness. People most at risk of this include older adults and people with severe chronic medical conditions like heart, lung or kidney disease. If you develop symptoms, contact public health authorities.

To prevent the virus from spreading, experts recommend frequent handwashing and coughing into your sleeve. They also recommend minimizing contact with others, staying home as much as possible and maintaining a distance of two metres from other people if you go out.

In situations where you can’t keep a safe distance from others, public health officials recommend the use of a non-medical face mask or covering to prevent spreading the respiratory droplets that can carry the virus.

For full COVID-19 coverage from Global News, click here.

— With files from Global News’ Laura Hensley & the Associated Press

Meghan.Collie@globalnews.ca

© 2020 Global News, a division of Corus Entertainment Inc.

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