Since the early stages of the COVID-19 pandemic, the use of masks has been discussed. As this pandemic continues, there has been a great deal of debate on this issue. This post is meant to help address some of the more common myths surrounding masks for COVID-19.
First, it is important to know that the evidence has been rapidly changing. Citing older studies is not effective in addressing this issue given how much has been learned by the scientific community and how much policy has changed as a result. There has also been a lot of opinion which does not mean much even from high profile resources (including medical journals) especially when they lack meaningful citations. For this reason, the studies mentioned have been carefully chosen to be most accurate to current information.
Myth 1 - Masks don't work!
This is probably the biggest argument of all, but there is a large amount of data. Let's start with the biggest study of all. Published on June 1, 2020 in The Lancet, Chu et al. collected 172 observational studies from 16 countries that included 25,697 patients. Their systematic review and meta-analysis supported physical distancing of 1 meter (approximately 3.3 feet) or more and the optimum use of face masks, respirators, and eye protection in public and healthcare settings. N95 respirators were better than regular face masks, but both were effective. This study found masks could lead to an 85% reduction in transmission.
Airborne transmission has been considered the dominant route for the spread of COVID-19. Proceedings of the National Academy of Sciences of the United States of America (PNAS) published a research article by Zhang et al. on June 30, 2020 covering this issue. They discussed how the virus is airborne in nature and a major reason for the spread. By studying mitigation measures in Wuhan, Italy, and New York City they found that protective measures including face masks in public reduced the number of infections by over 78,000 in Italy and over 66,000 in New York City over the course of a month or less. Check the two figures below both to better understand the airborne transmission and see how face coverings made the largest difference in transmission compared to other interventions.
Transmission of COVID-19. Human atomization of viruses arises from coughing or sneezing of an infected person, producing virus-containing droplets (>5 μm) and aerosols (<5 μm). Virus transmission from person to person occurs through direct/indirect contact and airborne aerosol/droplet routes. Large droplets mainly settle out of air to cause person/object contamination, while aerosols are efficiently dispersed in air. Direct and airborne transmissions occur in short range and extended distance/time, respectively. Inhaled airborne viruses deposit directly into the human respiration tract.
Contrasting the trends of new infections between NYC and the United States. Daily new confirmed infections in (A) NYC and (B) the United States. The dotted lines represent linear fitting to the data between April 17 and May 9 in NYC and between April 4 and May 9 in the United States. In B, the number in NYC was subtracted from that in the United States. The vertical lines label the dates for social distancing, stay-at-home orders, and mandated face-covering.
Proactively masking makes the biggest difference. As the study in Infectious Disease Modeling by Eikenberry et al. published on April 21, 2020 demonstrated, the earlier masks are used, the greater the effect in preventing cases. This is even true in worse case scenarios where masks are only 20% effective in situations where transmission rate is relatively low or decreasing.
Many have argued that the virus particles are too small to be stopped by even N95 respirators. While individual particles can pass through, transmission is usually in the form of droplets which are much larger in size. The New England Journal of Medicine (NEJM) published a correspondence by Anfinrud et al. on May 21, 2020 that helped tackle this issue. While large droplets tend to fall to the ground quickly, small droplet can linger in the air even for several hours. They performed an experiment using lasers to observe droplets during speaking. Generally, with louder speech, coughing, or sneezing the droplets become larger in size. However, a simple cloth mask was able to significantly reduce the amount or droplets released even with normal speech. This should carry over to be even more effective with the larger droplets released by louder speech, coughing, or sneezing making simple masks even more effective in such situations.
What about when masks are mandated or used throughout a population? Health Affairs published a study on June 16, 2020 by Lyu and Wehby covering this exact issue. They studied 15 states plus Washington DC for the period between April 8, 2020 and May 15, 2020 and found that 230,000 to 450,000 cases of COVID-19 were possibly averted by these mandates.
There has been concern regarding the public appropriately using masks. The Royal Society on June 10, 2020 published a research article by Stutt et al. that assessed the likely effectiveness. They found that when face masks were used all of the time in public (not just when symptoms first appear) it can lead to the mitigation of epidemic spread. Additionally, even if masks are only 50% effective at capturing virus particles that are exhaled (able to filter through the mask) they are still effective for this purpose. They also addressed the concern that face masks may be ineffective because wearers may touch their faces more often. Even in such situations, the population level benefits were still strong in reducing the overall spread significantly. It helps support the thought process of "my mask protects you, your masks protects me" that many of us have heard. The importance of using and cleaning masks correctly is still vital.
To build on the point that face masks work, the CDC has given a great review that helps keep this information to the basics. It mentions situations where face masks should be used, how to use them correctly, and other potential protective measures such as face shields. This is part of a larger CDC section that discusses cloth face covers and includes topics about how to wear, make, and clean cloth face masks. Remember, asymptomatic spread is still a real concern with multiple papers demonstrating the same. As it is pointed out there, and should be remembered here, these masks are less about protecting the wearer and more about reducing spread.
Myth 2 - Even the experts said not to wear masks or that they don't work!
This is an easy one to be confused by, and this is a great example of how new evidence helps change the practice of medicine. Huo Jingnan of National Public Radio (NPR) published a great piece called "Why There Are So Many Different Guidelines For Face Masks For The Public" on April 10, 2020. It leads off with the tweet by Dr. Jerome Adams on February 29, 2020 that is shown below. However, on April 3, 2020 the CDC starting recommending cloth face masks. On the same date, Dr. Jerome Adams even had a YouTube video demonstrated how to make your own mask and has been included below.
As the NPR article discusses, one important factor for some of the early recommendations was for fear of shortages and this is also reflected by the tweet by Dr. Jerome Adams. While initially they said healthy people should not wear a mask, CDC and WHO have since made it clear that they support the use of wearing a mask even in those without symptoms. Again, when you see posts regarding what was said, check the date of the original piece. You will find this was an old recommendation. We have also discussed quite a bit with the previous myth how masks work.
Some will point to what California's OSHA said that masks do not protect users. This was from one post on May 13, 2020 andCalifornia's OSHA has since advocated for mask use. Check their informational poster which is attached below. Also, OSHA at the national level has recommended that masks should be worn.
Some will ask about the FDA and point to statements they have seen. The two most common is that they do not recommend N95s and that N95s do not prevent illness or death. In fact with the latter one it is misquoted as, "Even a properly fitted N95 mask does not PREVENT illness or death." The actual quote from the FDA website says, "However, even a properly fitted N95 respirator does not COMPLETELY ELIMINATE the risk of illness or death." The all capital letters are placed to emphasize the key difference and not actually on the website this way. This matters because it does acknowledge that N95s are not perfect. They are still very good and can help reduce the wearer's risk of contracting COVID-19.
The other misquote with the FDA is that they did not recommend N95s. This is half true as that same article (last updated April 5, 2020) as above mentioned how the CDC did not recommend the general public wear N95 respirators. They explain, "Those are critical supplies that must continue to be reserved for health care workers and other medical first responders, as recommended by current CDC guidance." It is clear that they do acknowledge the benefit of N95s, but recognize it as a limited resource and should be reserved for certain populations.
Myth 3 - Masks will weaken our immune system!
This one is from a gross misunderstanding of how our immune system works. The concern is not just in regards to masks but social distancing and shelter-in-place orders. Where this originates from is what is known as the hygiene hypothesis. However, this has been more studied in regards to its role with asthma and allergies. What is actually being discussed is more of an up regulation of the immune system (an over response) which would be the exact opposite of the "weakened" immune system.
More precisely, the real problem with the hygiene hypothesis are the implications it has on public health issues including the spread of infectious diseases (like COVID-19). A well done article by the Microbiology Society published on March 28, 2019 (almost a full year before COVID-19 was declared a pandemic) addresses this exact issue and is well worth the read. It discusses how protective measures (such as hand washing and household cleaning) is vital to reducing the spread of infections. Masks would fall in that same category.
Additionally, consider the human body in general. It has normal flora with a variety of bacteria and other organisms living both inside and outside of it. A number of surfaces also carry commonly exposed flora which our body has already seen and continues to identify. This is not simply changing with masks or other barriers of protection. People are still leaving their environment whether it is to go outside, go to a grocery store, or come into contact with flora during any number of countless activity. If all it took was a few weeks of such conditions, the human race would most likely have not survived far before this point.
Myth 4 - If I wear a mask I will get CO2 poisoning or not enough oxygen!
This is an example of another case where basic science carries the answers. There is an article from the British Broadcasting Corporation (BBC) written by Goodman and Carmichael published on June 20, 2020 that goes into great detail discussing this topic. To summarize what is basic biology is that carbon dioxide (CO2) is incredibly small in size and able to filter through a mask. CO2 will go through and around the mask. The same is true as someone breathes in oxygen (along with the other molecules in air such as nitrogen). These all easily filter and would not be trapped by the breathable material that would be worn by users.
Think about this for a moment. Those who work in surgery, certain construction and other specialty fields, and now large sections of healthcare (many hospitals, nursing homes, etc) are wearing masks all day. Many of these masks will be heavier duty in nature including N95s. It is incredibly rare to find any actual harm that has been documented and can only be found in rare situations with N95s. One such paper was published in the American Journal of Infection Control by Rebmann et al. on June 12, 2013. They found the combination of a mask and N95 resulted in more symptoms than a N95 alone along with an increase in CO2 that was not clinically relevant. Keep in mind that the wearers had their masks on for 12 hours which would be well beyond the period of time most people would wear a simpler (more breathable) mask in public. An article published October 29, 2012 by Sinkule et al. in The Annals of Occupational Hygiene is very similar. Again, the concern is mild and really only appears to be in combination of a surgical mask over a N95. A simple surgical mask of cloth mask does not carry the same concerns.
If someone is still having difficulty with wearing a mask, there are some helpful articles like this one published on Yahoo News by Renee Fabian on May 14, 2020. It covers a wide range of topics including masks for children, those with anxiety when wearing masks, and those with sensory sensitivities.
Myth 5 - Requiring masks is a way to take away our freedom and promotes living in fear!
This myth is largely due to the political and polarizing world we live in. Individualism in the United States also plays an important role. Most people living in the United States are not used to either wearing masks or altruism, especially toward strangers. In Asian countries, masks are frequently worn and part of this dates back to the SARS outbreak of 2003.
Politics carries part of the blame here, but this may be changing. Some have tried to argue that this is unprecedented in the United States (and elsewhere), but this is simply not true as history continues to remind us of how we tend to repeat ourselves. Masks have been mandated in the past including the 1918 influenza pandemic. "Mask slackers" were common with the 1918 influenza pandemic and there was the Anti-Mask League in San Francisco. Many of the same concerns were brought up then but we can also see how such measures were vital (along with others) to help reduce the spread of infection.
Dr. Jerome Adams has also tried to explain that masks are not meant to suppress freedom but rather to help open up more places sooner allowing for more freedom of movement and activity. Again, this is not an issue of impeding on someone's freedom, but more about protecting others with something that (as we have discussed throughout this post) can be very effective especially when worn by most if not all of a population.
This leads to addressing the second part of this myth: masks promote fear. Masks help reduce the spread of this and other infections. Not only by reducing droplets and the amount of viral particles released but also to help remind us that physical distance should be maintained. Masks can act as a reminder of the social contract we have to help keep each other safe. For these reasons, masks should not be considered to promote fear, but rather to promote selfless acts to help serve and protect others.
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