Myth or Fact: Common Misconceptions about Face Masks.

As COVID-19 cases continue to surge in the U.S. — particularly in states like Florida, Texas and Arizona — the use of face coverings has become a flashpoint amongst people. Wearing a mask is essential for slowing the spread of the virus. With rumors and false information spreading as fast as the virus, many people are not convinced of the need to wear one.

Here we look at some of the more common myths surrounding the use of masks and provide factual evidence to support wearing them.

Myth: Wearing a mask can cause hypoxia (oxygen deprivation) or hypercapnia (carbon dioxide poisoning).

Fact: Neither the reduced amount of oxygen coming in nor the trapped carbon dioxide caused by wearing a mask is enough to be harmful. 

The risk of hypoxia and hypercapnia are essentially impossible. The filters in face masks are meant to be small enough so droplets containing infectious agents are filtered. Smaller gas particles, like oxygen and carbon dioxide, can pass through freely.

Masks and face coverings are worn daily, and often for extended periods of time, in many  professional settings, such as during surgery and while conducting scientific research. This practice has been utilized for years and has shown to cause no harm or impairment. In fact, after the CDC revised its previous guidance on masks and recommended their use, the Brigham and Women’s Hospital in Boston reported that the infection rate of COVID-19 amongst the hospital staff dropped by nearly half due to their required masking policy.

If worn properly, masks  can significantly reduce the risk of spreading the COVID-19 infection. If you want to test this for yourself, use a pulse oximeter and compare your oxygen saturation levels, the oxygen level in your blood, while wearing and not wearing a mask.

Myth: Only those who are already infected or those who have a weaker immune system should wear masks.

Fact: In reality, in order to slow the spread of the COVID-19 infection, everyone needs to wear a mask.

Recent studies have shown that the infection can be transmitted for more than 14 days and is often transmitted silently, i.e. without knowing it. Between 40-45% of COVID-19 infections are asymptomatic. Because of this, it is crucial that everyone wears a mask, not only those who are sick, older, or have a weakened immune system. When a person does not wear a mask, they can spread infected droplets containing the virus, particularly if they are asymptomatic. After mask wearing was mandated in communities, studies have shown that the daily growth rate of COVID-19 was slowed, and continued to be reduced over time with the use of masks.

One compelling case report illustrated the need for the use of masks for the prevention of transmission.  A man who tested positive for COVID-19 flew from China to Toronto and wore a mask on the flight. Thanks to his wearing a mask, the 25 people closest to him on the flight all tested negative for COVID-19.

There are many types of masks, medical and homemade, available on the market.                N95 respirators, KN95 masks and surgical masks are all examples of medical masks that can be used to decrease the spread of the virus. Since these are often hard to obtain, the CDC has provided tips for how to create a homemade cloth face covering on their website. There are other options as well, like using a bandana or scarf.  

Learn how to make your own face covering here:   



Johns Hopkins University

UT Southwestern Medical Center

University of California San Francisco

Center for Disease Control

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