Question: Health officials have been urging people to wear face masks in public places. Is the goal to prevent me from spreading COVID-19 to other people if I’m infected? Or, is it to shield me from others who might be infectious? And do I need a special type of mask if I want to protect myself?
Answer: You may have noticed that advice about masks has changed during the course of the pandemic as the medical community has gained a better understanding of SARS-CoV-2, the coronavirus that causes COVID-19.
Experts agree that the virus is primarily transmitted through physical contact and respiratory droplets from an infected person coughing, sneezing and talking within close range.
The big challenge is that some people can spread the virus for up to two days before they experience symptoms, says Dr. Jerome Leis, medical director of infection prevention and control at Sunnybrook Health Sciences Centre in Toronto.
And certain cases are so mild that infected individuals may never grasp that they caught the virus.
This is very different from other viral respiratory infections that tend to produce obvious signs of illness, indicating when a person poses a risk to others.
The realization that COVID-19 could be transmitted unwittingly has led many experts to call for the universal use of masks in certain public places – especially indoors and where it may not be possible for people to keep at least two-metres apart.
For the general public, any cloth or fabric mask can effectively trap the respiratory secretions at their source – the nose and mouth – so they don’t spread to others or contaminate nearby surfaces.
“If two people are wearing masks properly, with the nose and mouth covered, then both are protected from each other,” says Dr. Leis.
But in health-care institutions, medical-grade masks are necessary to safeguard staff, says Dr. Susy Hota, medical director of infection prevention and control at the University Health Network, a collection of medical centres in Toronto.
“We are caring for people who are often the sickest and most infectious with COVID-19. And a sick patient in a hospital room may not be wearing any mask,” she explains.
What’s more, patients may require invasive respiratory procedures that can fill the surrounding air with tiny aerosol particles containing the virus.
“It’s a pretty high-risk scenario,” says Dr. Hota.
In order for health-care workers to be in close contact with COVID-19 patients to perform these procedures, they need special masks called respirators that prevent them from inhaling the virus.
There are different types of medical-grade masks, designed for a variety of situations. A key feature of some masks is that the outer layer is hydrophobic, which means it repels and won’t absorb any liquid droplets that might land on it.
Dr. Hota says it’s important to conserve supplies of medical masks for those who need them the most – front-line health-care workers.
Even so, some people may still try to acquire these special masks online or in stores.
However, they may not be getting the real thing, says Dr. Leis. “You may buy a mask that looks identical to one that is used in health care, but it might not meet the basic requirements in terms of fluid resistance and fit.”
He notes that hospitals follow procedures to ensure masks conform to certain specifications. The products available to the public may not go through the same level of rigorous testing.
But if your own safety is your primary concern, you can take some comfort in the fact that even a homemade mask “when it is well-designed and uses the right materials” can provide some degree of protection to the wearer, says Dr. Hota.
Indeed, if the outer surface is a droplet-resistant fabric, then it can act as a shield that stops the virus from entering the nose or mouth. Of course, you also need to take off the mask properly and wash your hands so germs aren’t scattered around.
Ordinary face coverings – if used correctly – can certainly curb new infections.
The widely-reported case of two hairstylists in Springfield, Missouri, illustrates the effectiveness of universal masking. The two women cut the hair of 139 clients while they were highly infectious. Fortunately, local regulations required the hairstylists and clients to use face coverings. After tests revealed the women had COVID-19, public health officials tracked down all their clients. The investigation revealed not even one of them caught the bug.
In some ways, donning a face covering is an altruistic act because the primary purpose is to prevent the person wearing the mask from transmitting germs to others. But when everyone puts on a mask, we end up safeguarding each other. It’s a bit like the old saying, “You scratch my back, and I’ll scratch yours.