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A Surgical Mask Won't Protect You From Coronavirus

The masks are designed to prevent you from infecting someone else with your germs, not to prevent someone else’s germs from infecting you.

This article was first published in The Montreal Gazette.

The following is a public service announcement: Please stop stealing masks from your doctor’s office. I realize that people are worried about coronavirus, but before you commit petty theft, you should probably know that those masks won’t protect you from catching the virus.

On the off chance that you haven’t heard, the coronavirus has been declared a global health emergency by the World Health Organization. [At the time this article was written], it has infected more than 28,000 people and caused 565 deaths worldwide. To put this in perspective, the flu has infected 22 million and killed some 12,000 people during this flu season in the United States alone, which makes it a much more dangerous virus.

Still, the coronavirus outbreak does pose a risk if not properly handled. It was, after all, a coronavirus strain that caused the SARS outbreak of 2002 and the MERS outbreak in the Middle East in 2012. For those who knew people in Toronto during SARS, especially for those who had friends in the health care field who got sick, the memory of that episode is still fresh. But surgical masks are not going to help.

Many doctors’ offices have boxes of surgical masks laid out at reception for patients who come in with symptoms like sneezing or coughing. These are provided so that sick patients will not spread their germs to others in the waiting room. But colleagues of mine have told me that some patients are leaving with fistfuls of surgical masks or simply taking the box altogether. The result has been a global shortage of masks. The other day, I went to the pharmacy, and as I walked in the door the clerk told me that they were out of surgical masks and would probably not get more anytime soon. I told them that I just came in to buy some shampoo.

There are several problems with this run on masks. First, stealing is wrong. But more important, the regular surgical masks that some people seem to be hoarding won’t actually protect you from coronavirus.

Most common infections are spread via droplets. In other words, every time you cough or sneeze when sick, tiny water droplets that contain virus particles are sprayed around you. These can directly infect someone close by, or can land on a nearby surface like a table or a chair. Someone might then touch that table and put their hand to the eyes, nose or mouth and thus transmit the virus to themselves.

The problem with standard surgical masks is that they are not airtight seals around your mouth and nose. Someone can still cough on you, and infect you or you can still touch contaminated surfaces and infect yourself. People often ask why doctors are often seen wearing surgical masks throughout the hospital. The answer is that the masks are designed to prevent you from infecting someone else with your germs, not to prevent someone else’s germs from infecting you.

If a doctor wanted to protect themselves from an airborne infection, they wouldn’t wear a surgical mask. They would wear an N95 mask. The N95 mask actually provides good protection against airborne infections, but it has two drawbacks. To work, it has to be fitted properly to your face. Second, I can say from personal experience that after about 20 minutes of wearing a N95 masks you start to become lightheaded and feel unwell, likely because you have been rebreathing increasingly stale air. It’s not the type of thing you can wear for hours.

It’s understandable that people are scared about coronavirus, but wearing a surgical mask won’t really do much to protect you. Though given that only seven people in Canada are infected with coronavirus, you probably don’t need much protection to begin with.

For up-to-date numbers on the spread of coronavirus, Johns Hopkins created this very useful online dashboard.


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