National Post (National Edition)
NOT ALL FACE MASKS ARE CREATED EQUAL
WHAT YOU NEED TO KNOW TO PROTECT YOURSELF
The message to Canadians over the last few weeks has been clear: Don’t buy face masks. Personal protective equipment is in short supply. Priority must go to frontline health workers, our best line of defence against the virus — and the most vulnerable to catching COVID-19. Most people are unlikely to wear a face mask correctly anyway. And masks only protect others, not the wearer.
So why did Dr. Bruce Aylward, one of the leads on a WHO-China Joint Mission on COVID-19, wear a face mask during a recent presser — despite the fact that the WHO says healthy people only need masks if they’re taking care of someone sick?
And why have the governments of Austria, Czech Republic, and Slovakia decreed mandatory mask-wearing for anyone who leaves their house? China, Japan, Taiwan and Hong Kong have also recommended citizens wear face masks. Germany and South Korea have banned face mask exports to prioritize it for their own populations.
Dr. Elaine Shuo Feng, an epidemiologist and statistician at the Oxford Vaccine Group in the U.K. who authored a paper on the rational use of face masks in The Lancet last week, says while masks could help reduce transmission, there are different types of masks — and some are more important for health-care providers than others. Here’s a quick guide.
N95 RESPIRATORS: GOLD STANDARD FOR HEALTH WORKERS
First things first: N95 is a designation, meaning they are approved for medical use by Health Canada. Masks with that name, in varied shapes including cups, flatfold or duckbill, must be able to filter out at least 95 per cent of very small particles.
To do that, N95s require fabric with pores no more than 0.3 microns in diameter, or 300 nanometres. Manufacturers use what’s called “meltblown” fabric made from interlaced polypropylene fibres (think a cotton candy maze trapping particles as they travel) that are notoriously hard to produce.
However, all this hard work goes to waste if the mask is not fitted properly. N95 wearers often have to remove any jewelry and facial hair, and health-care workers are fit-tested for N95 respirators before actually using them to make sure they are completely sealed against their faces — otherwise, viruses will still sneak in the sides.
Health Canada also notes that “Both respirators and masks need to be used in combination with appropriate eye protection (e.g., face shield, goggles) to achieve full protection of the eyes, nose and mouth.”
Should you see N95s for sale, also note that they have a “best before date.”
SURGICAL MASKS: THE NEXT BEST THING
In many East Asian countries, these loose-fitting face masks — made from fabric or polypropylene — have been in widespread use for many years. They offer protection against 80 per cent of tiny particles, and block out air pollution. Given the challenges of fitting medical-grade face masks, a 2016 CMAJ review found they were nearly as effective as N95s.
Although surgical masks are not designed protect the wearer — they are made to protect patients from any droplet contamination from a doctor during surgery — they are being used as a contingency tool even in hospitals. Troubling for many health-care workers, that means reusing masks that are meant for single use.
HOMEMADE: A LAST (AND SUSTAINABLE) RESORT
There is not a lot of evidence about the effectiveness of homemade masks. In a small 2013 study, researchers found masks made from cotton T-shirts (which had been tested to fit properly) were better than no protection but “should only be considered as a last resort.”
That last resort has arrived in many jurisdictions, however: In Toronto, Michael Garron Hospital has
NO MATTER WHAT TYPE, MASKS ARE NOT A CATCH-ALL.
made a plea for donations of as many as 1,000 homemade masks — every week. They even uploaded a simple face mask sewing pattern that can made from bedsheets, T-shirts, or tea towels.
THE DOWNSIDE OF FACE MASKS
No mask will be perfect against the virus. Coronavirus particles are actually smaller than the regulation pores of even N95 masks.
Masks can also lead to a sense of “false security,” said Canada’s top doctor, chief public health officer Dr. Theresa Tam in a media briefing on Monday. You may be touching your face more. (Never touch the front of the mask.)
Feng adds that many people wear a mask with their nose or mouth exposed, rendering it completely useless.
There’s also the potential this virus can be transmitted through the eyes. “How much false security do you give to people by having them use masks? Unless they’re physical distancing, there is still the potential for transmission even though the mouth and the nose are covered.”
THE BOTTOM LINE
For all of their flaws, masks are a useful tool to prevent infection — if combined with staying at home, physical distancing, and washing your hands with soap.
No matter what type, masks are not a catch-all, says Dr. Jason Kindrachuk, a medical microbiologist and the Canada Research Chair in Molecular Pathogenesis of Emerging and Re-Emerging Viruses at the University of Manitoba. He stresses that physical distancing is still the absolute primary point the general population needs to be doing — since healthcare workers can’t.