Now that the chilly climate has hit and people are transferring inside, many docs and scientists are urging Canadians not solely to withstand getting complacent about carrying masks to guard towards COVID-19 — but additionally to take a more in-depth have a look at whether or not that fabric masks is holding you and others as secure as doable.
“In general, while non-medical masks can help prevent the spread of COVID-19, medical masks and respirators provide better protection,” the Public Health Agency of Canada (PHAC) mentioned on its COVID-19 mask information webpage, which was up to date on Nov. 12.
The up to date steerage additionally recommends medical masks or respirators for people “who are at risk of more severe disease or outcomes from COVID-19” and these “at higher risk of exposure to COVID-19 because of their living situation.”
Respirators — comparable to N-95 and KN-95 masks — are thought of the very best degree of masks safety and have been beforehand advisable just for health-care staff coming into direct contact with infectious sufferers. In these high-risk areas, respirators require a “fit test.”
But in a nod to extra basic use, PHAC’s steerage now says: “A respirator worn in the community doesn’t need to have been formally fit tested, as is required in some occupational settings.”
Responding to a CBC News inquiry about why PHAC’s suggestions have modified, the company mentioned in an e mail it was “based on the latest scientific evidence on SARS-CoV-2 virus variants of concern, increased understanding of the impacts of vaccination and immunity in the population, and new data available on mask types and their effectiveness.”
In addition to the up to date on-line steerage, Dr. Theresa Tam, Canada’s chief public health officer, just lately posted a sequence of tweets illustrating how COVID-19 may unfold by way of the air, utilizing the analogy of second-hand smoke.
1/5 Layering <a href=”https://twitter.com/hashtag/COVID19?src=hash&ref_src=twsrc%5Etfw”>#COVID19</a> protections is finest! Evidence on aerosol unfold of the <a href=”https://twitter.com/hashtag/SARSCoV2?src=hash&ref_src=twsrc%5Etfw”>#SARSCoV2</a> virus reveals that expelled virus particles can unfold over distances and linger in nice aerosols for durations of time, very like second-hand smoke. <a href=”https://t.co/V5p7kz3ioX”>https://t.co/V5p7kz3ioX</a>
Many docs, scientists and engineers say this shift in messaging displays a rising physique of proof suggesting that COVID-19 is basically unfold by way of aerosols (tiny particles that can dangle within the air), and never simply by way of respiratory droplets (bigger particles) transmitted by shut contact with an contaminated individual.
In flip, that means it is vital to re-evaluate the masks we’re utilizing, they are saying.
“This marks a transition in Canada toward a recognition of how important aerosol, airborne-based transmission is in transmission of this virus,” mentioned Dr. Brooks Fallis, a vital care doctor on the Toronto-area William Osler Health System.
Because aerosol particles are smaller and might accumulate within the air over time, Fallis mentioned, the best-performing masks are vital if you are going to be indoors with other people for a while.
“If you’re just, you know, popping into the grocery store to grab a couple of items, or you’re … walking along a crowded street and you want to wear a mask, then it’s fine [to wear a medical mask],” Fallis mentioned.
“But if you’re in a closed space with lots of people, then we should be upgrading to higher-level masks, like the KN-95 masks or a respirator-type mask, which provides better fit and better filtration.”
Masks are vital even when you are totally vaccinated, each PHAC and docs say, as a result of though it is a lot much less probably, an infection with the virus that causes COVID-19 — particularly the extremely transmissible delta variant — can nonetheless occur.
Better availability of higher-grade masks
Another vital issue that’s modified for the reason that starting of the pandemic, specialists say, is the provision of medical/surgical masks and respirators.
“There was a lot of controversy about N-95 masks because there weren’t enough for the health-care workers. So the message then, quite understandably, was: ‘Save those for the health-care workers and we will use other alternatives,'” mentioned Marianne Levitsky, an industrial hygienist with the Dalla Lana School of Public Health on the University of Toronto.
“But things have changed a lot. We now have Canadian manufacturers making N-95-type masks and they’re much more widely available than they used to be,” she mentioned.
Experts agree any masks is healthier than no masks, as a result of it will catch droplets and aerosols coming from the wearer’s nostril and mouth and defend others. But there’s rising proof that a higher-quality masks can even present some safety for the wearer.
“The masks or respirators, they control in two ways. One, they can prevent an infected person from emitting those infectious aerosols into a space, and they can also protect the person who is wearing them from inhaling them,” mentioned Levitsky.
“Cloth masks were always sort of something that was going to buy us some time as we move toward something better,” mentioned Conor Ruzycki, a PhD candidate in mechanical engineering on the University of Alberta who research aerosol science and expertise.
“Now that we understand this disease better, we know that these small aerosols are playing a bigger role; we should be moving toward … using better mask materials.”
The 3 Fs of selecting a masks
There are three F-words to bear in mind when assessing how nicely a masks will defend you and others: Fit, filtration and performance (additionally referred to as breathability).
“Fit is essential in terms of how effective filtration happens in a real setting,” mentioned Ravi Selvaganapathy, a professor of biomedical engineering on the Centre of Excellence in Protective Equipment and Materials at McMaster University.
“You can have the best quality material out there, but if it doesn’t fit one’s face, then most of the air goes through these large gaps that exist and not through the filter material.”
The filter materials in each medical/surgical masks and N-95 respirators is definitely the identical — however respirators contour higher to an individual’s face, mentioned Selvaganapathy.
A “knot and tuck” adjustment can enhance the match of disposable masks — together with medical masks, the Centers for Disease Control and Prevention (CDC) advises.
“Knot the earloops of a three-ply face mask where they join the edge of the mask,” the CDC web site says. “[Then] fold and tuck the unneeded material under the edges.”
Cloth masks typically supply good match and good operate (breathability), however how nicely they filter out virus particles is often a wild card, specialists say, as a result of they’re manufactured from various supplies and are not regulated.
“There are no standards. When you buy a cloth mask, it does not usually tell you what the filtration is,” Levitsky mentioned. They can defend wherever from 20 per cent to 80 per cent, she mentioned. “So it’s a big unknown.”
Filtration for medical/surgical masks and respirators is graded by the requirements group ASTM International. And some non-cloth, non-medical masks stocked in shops could appear like medical masks — however aren’t, specialists say, so it is vital for customers to test the label.
The ASTM has began a voluntary certification program for non-medical masks, however at this level, there aren’t many licensed non-medical masks accessible.
In an effort to raised curb COVID-19 transmission, some international locations, like Germany and Austria, have mandated medical-grade masks and respirators as a substitute of material masks in public areas.
In many cases, they have been distributed at no cost or sponsored, mentioned Fallis — a transfer he’d wish to see Canada make.
“I think that’s a worthwhile investment because it’s another way to bring cases down [and] to make higher-quality masks a little bit cheaper, particularly to people … [for whom] it’s a financial burden to be purchasing masks,” he mentioned.