COVID-19 and protective masks: It’s more complicated than you think
At the time of writing (March 2, 2020), protective face masks are not recommended in Canada or the U.S. for protecting healthy people in the community from COVID-19. This is for the following reasons:
1. Most people don’t know how to select or use masks. Most people don’t know that there are various kinds of protective masks and that some are better than others at filtering particulate matter. More importantly, most people don’t know how to fit masks around their face or that facial hair can hamper the seal of the mask. The CDC has published an interesting info-graphic on the latter topic.
2. Masks offer a false sense of security. Masks won’t protect you if you touch a contaminated surface and then rub your eyes or touch your fingers to your mouth or nose. A mask can only protect you from inhaling droplets or aerosol containing the virus. Wearing a mask does not mean that you should ignore all the other advice about hand hygiene and hand-face awareness.
3. If the general public buys up the supplies of masks, particularly the N95 respirator masks, then this raises concerns about whether healthcare workers will have an adequate supply of masks.
So, the general public is told not to wear masks, but healthcare workers, who routinely come in contact with infectious patients, are advised to wear masks. Some people find these recommendations to be inconsistent or confusing. The public shouldn’t wear masks but healthcare workers should?
The recommendations are based on systematic reviews of the research literature (e.g., Jefferson et al, 2011; Offeddu et al., 2017; Saunders-Hastings et al., 2017). But if you look more closely at the research, the picture is more complicated than the simple message we receive from health authorities. The research on this issue is uneven in terms of scientific rigor, and there are many methodological complexities. To investigate the question of whether masks are protective for the healthy, general public, a critical issue is whether people are consistent in wearing the masks. Sometimes that isn’t examined in research studies. Instead, the researchers might simply ask a yes/no question such as “do you wear a protective mask?” This doesn’t take into consideration how consistently people wear masks.
A question of greater importance has to do with the prevalence of respiratory illness in the community. If you wear a facemask and almost no one around you is sick, then obviously a facemask will be of little benefit. And, indeed, that is what the studies have shown. But what if many people around you are sick? What if you’re in mass gathering where, say, a third or more of the people around you have respiratory illnesses? That situation might approximate a healthcare setting; that is, a setting in which healthcare workers are advised to wear masks. Research studies on mass gatherings, such as the Hajj, have investigated this issue. In these settings many people acquire respiratory symptoms (mostly minor) as a result of being in proximity with so many other people. Research suggests that in these situations, a facemask may protect you from getting a respiratory infection. These studies looked at minor symptoms but nevertheless the findings suggest that if COVID-19 becomes widespread throughout your community, then it would be prudent to wear a mask. Indeed, it might be mandated, as has been done in other countries and in past outbreaks.
The bottom line is that the wisdom of wearing masks for the general public depends on the health of your community. If almost no one in your community has COVID-19, then it is pointless to wear a mask. But if many people in your community are sick and not self-isolating, then it would be prudent for you to wear a mask. It is for this reason that I bought a box of N95 respirator masks 18 months ago when I first started working on my book, The Psychology of Pandemics. I haven’t opened my box of N95s or handed out the masks to my family. That isn’t necessary right now. But I’m monitoring the situation.