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In Canada, governments have strongly recommended that the public – such as those seen here on April 19, 2020 in Vancouver – wear masks.DARRYL DYCK/The Canadian Press

Felix Li is a retired public health specialist and epidemiologist. Dr. Li has more than 30 years of experience, including 23 with the Public Health Agency of Canada, where he actively participated in previous outbreaks of SARS, H5N1, H1N1 and H7N9.

The U.S. Centers for Disease Control and Prevention and the Public Health Agency of Canada have both wisely recommended the use of cloth face coverings for the general public. These agencies, however, still maintain that doing so only protects others, and not the mask user.

By doing so, the benefits of widespread mask wearing are played down and minimized – and more lives are at risk.

In January of this year, the World Health Organization’s advice stated that in community settings “a medical mask is not required, as no evidence is available on its usefulness to protect non-sick persons.”

Health authorities in many countries, particularly in the West, have made similar recommendations to their citizens: Wear a mask to protect others and stop the spread, because you may have the coronavirus that causes COVID-19 and be asymptomatic. Importantly, the same WHO document also recommended health care facility workers and home-care caregivers “should wear a medical mask when entering a room where patients suspected or confirmed of being infected with 2019-nCoV.”

If that is the case, if masks can protect the wearer in that hypothetical scenario, wouldn’t we all be better off wearing one?

The CDC’s 2007 Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Health Care Settings (revised July, 2019) recommended using a surgical mask by health care personnel to protect themselves from diseases with droplet transmission. Similar Canadian guidelines (revised December, 2017) recommended health care workers wear a mask (for droplet protection) when working within two metres of an influenza patient.

All these recommendations are based on sound scientific research. While there is abundance of scientific evidence that surgical masks can protect health care workers from droplet-transmitted diseases, including COVID-19, some health authorities still maintain that somehow the same mask cannot perform the same function for the general public?

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Are they all not human beings, with the same general anatomy and physiology? Let’s be frank: Masks can protect all people against droplet-transmitted diseases such as COVID -19. The only difference here is that the general public has a relatively lower risk of exposure to the virus than health care workers.

But right now, when we’re all acting out of an abundance of caution, let’s be clear: If you wear a mask, your risk of contracting the virus – even if it’s low to begin with – will be reduced.

Some have argued that although a mask can protect you from COVID-19, you really don’t need to wear one because of the low risk of exposure in the general public. Tell this to people who were deemed low risk to COVID-19, but died or suffered extensively from the disease.

Students and teachers in public health should be familiar with legendary epidemiologist Geoffrey Rose’s concept of the “prevention paradox” – population strategies which reduce the low risks of many in the population can be more effective at improving overall population health than high-risk strategies, which reduce the high risk of a smaller sub-populations. This is because the vast majority of cases usually originate from the low-risk groups.

So should we enact strategies that protect low-risk swaths of the population?

Certainly, there is a big difference in the magnitude of risk to health care workers tending to COVID-19 patients compared with the general public, and N95 respirator masks and surgical masks should be reserved for these workers exposed to high risk. But cloth face coverings can – and should – be used by the general public, at least in the interim before we can acquire adequate supplies of masks.

Incidentally, places such as Taiwan, Hong Kong and Singapore, which prepared for the pandemic early, have managed to provide masks for their health care workers as well as their citizens en masse. Here, governments have strongly recommended that the public wear masks.­

Clearly, we would all be at a reduced risk for contracting the virus if we wear mask coverings. In order to lower the risk and slow the spread, this fact should be clearly broadcast to the general public. Individuals have a right to make their own decisions to protect themselves based on accurate information provided by global and local health authorities.

Now that it is recommended you wear a face covering in dense public settings like grocery stores and pharmacies, watch how to make the three masks recommended by the Centers for Disease Control and Prevention. Written instructions available at

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