Wednesday, February 24

Your questions, our answers | Should the masks be superimposed to be better protected?

Do you have questions about COVID-19 and vaccination? Journalists from Press respond directly to your questions on the subject.

Judith LachapelleJudith Lachapelle

First of all, it was important not to wear it. Either way, whether it was washable or disposable, standardized or DIY, the medical mask or the fabric face cover was hard to find. Then, its adoption was recommended and encouraged. And today, not only do you absolutely have to wear one, but according to some experts, you should even… wear two?

The Minister of Health and Social Services, Christian Dubé, presented himself at a press conference on Thursday with a double face protection: a medical mask under a fabric face cover. He said this was a personal initiative, not a recommendation from Public Health. “Sometimes doubling the mask in certain circumstances, I believe in it, and that’s why I do it as often as possible. ”

His statement came the day after the publication of a study by the Centers for Disease Control and Prevention (CDC) in the United States which showed that wearing a medical mask (the blue and white mask also called procedure mask or surgical mask) under a three-ply cotton face cover provided 95% aerosol protection.

Should we therefore double the number of masks we wear? Not necessarily.

The medical mask, used alone, can already block more than 95% of aerosols… when it is well worn. The problem is, it isn’t always. When this mask is not fitted properly on the nose or sides of the face, protection is greatly diminished – it was only 42% in the CDC study. The “double mask”, studied by the CDC, improves the fit of the protection on the face to ensure that air passes through the filter of the medical mask, and not to the sides.

To qualify things a little, the CDC study also recognizes that when two people each wear a well-fitting medical mask (for example by tying the elastics to allow the sides to be tightened), the effectiveness is the same (95%). than when superimposing face cover and medical mask

“It’s getting confusing”, admits the D himself.r Stéphane Perron, from the Institut national de santé publique du Québec (INSPQ). “But there are things that don’t change. The certified medical mask is the one that must be used in the workplace and that is recommended by the CNESST. When it is properly fitted, it is shown to protect both the wearer and others around them. ”

The INSPQ does not comment on the effectiveness of the fabric face cover because it is not subject to effectiveness standards. “So it’s of variable quality,” says Dr Perron. The fabric face cover helps block particles emitted by its wearer. At what point ? It all depends on the type of fabric, the number of layers, its fit …

We assume that the face covering protects others, but we don’t have a good demonstration that it protects us ourselves. This is why the INSPQ has always favored the medical mask.

The Dr Stéphane Perron, from the INSPQ

“And that is why, more and more, in public places where the wearing of a mask is required, the procedural mask is provided, such as at school or in hospitals”, adds the Dre Caroline Quach, microbiologist-infectious disease specialist at CHU Sainte-Justine.

The Quebec Ministry of Health recalls that it has recommended “since the summer that people who are more vulnerable to developing complications from COVID-19 wear medical masks”, its spokespersons said in an email. at The Press.

On the Health Canada side, the recommendations remain the same for now, either wearing a medical mask, or a fabric face cover ideally made up of three layers (one of which is made of a disposable filter or washable).

Other standards in Europe

While fabric face covers are not covered by certified standards in Canada and the United States, they are not everywhere. “In France, notes the Dr Perron, they have standardized face covers, which makes them almost as effective as medical masks. These standards do not yet exist here. ”


Wearing the FFP2 mask, similar to the N95, is now required in some European countries, including Germany and Austria.

At the end of January, with the appearance of the new variants, the French authorities recommended that citizens no longer use “artisan” face coverings. Three types of masks are now recommended in public spaces: the medical mask, the “FFP2” certified mask and the “category 1” certified fabric mask. The latter is made of three layers of fabric, two of which are cotton and one is a non-woven material (such as polyester) – a design similar to Health Canada’s recommendations.

The FFP2 certified mask is an equivalent of the American N95 and the Chinese KN95. Generally designed for single use, it is considered not to be breathable and less comfortable than medical masks or those made from “category 1” fabric. It is now required in certain public spaces in Germany and Austria.

The American proposal for the double mask has generally been received with more caution than enthusiasm by experts. France does not recommend it, but recognizes that it “may improve filtration”. In interview with the Vancouver Sun, Professor Steven Rogak, a specialist in the study of aerosols at the University of British Columbia, said that “the biggest problem is not to improve masks, but to inspire people who do not wear it at all to wear it ”. When dealing with variants, respecting physical distancing and wearing a well-fitting mask are generally seen as more important than overlaying layers of protection.

It is therefore not a “bad idea” to layer masks, but it is the fit of the mask that should be prioritized. “The problem with layering layers is that breathing becomes difficult,” adds Dr.r Perron. And if she becomes so to the point that you have to remove all her masks to take a breath of fresh air, no one comes out better protected …

“When will I get vaccinated? “

“When will my turn come?” », Ask us many readers. After residents of CHSLDs and other “intermediate resources” type establishments had been vaccinated, vaccination began in the third priority group determined by the authorities, namely “independent people or people with loss of autonomy who live in residence. private for seniors (RPA) ”. Vaccination of healthcare workers (group 2) and isolated and remote communities (group 4) continues. The next group on the list are those aged 80 and over (group 5) who are not living with APR, and whose vaccination should not start until the end of the month. Where should I register? When should you make an appointment? Patience, responds the Department of Health and Social Services. As soon as the vaccine supply allows it, the authorities will make the announcement and it will be possible to make an appointment on the Clic Santé site.

> Consult the list of priority groups to be vaccinated

> Do you have questions about COVID-19 and vaccination to submit to our team? Write U.S !

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