Should You Wear a Mask to Prevent COVID-19?

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States are increasingly mandating the use of face masks in public places, but evidence suggests face coverings do little to reduce risk of illness and, in some cases, may even increase your likelihood of contamination.

As recently as February 29, 2020, U.S. Surgeon General Jerome Adams tweeted, “Seriously people — STOP BUYING MASKS! They are NOT effective in preventing general public from catching coronavirus … ”[i]

Yet, in a dramatic about-face, weeks later the U.S. Centers for Disease Control and Prevention (CDC) said they recommend wearing cloth face coverings in public settings where social distancing measures are difficult to maintain, especially in areas with significant community-based transmission, and stated, “CDC also advises the use of simple cloth face coverings to slow the spread of the virus and help people who may have the virus and do not know it from transmitting it to others.”[ii]

At the state level, an increasing number of states have put in place recommendations and requirements for workers and customers to wear face masks in public. In Illinois, for instance, everyone is advised to wear a mask basically anytime they leave their home, including while shopping at grocery stores, getting food from drive thrus or curbside pickups, visiting a health care provider or traveling on public transportation.[iii]

In a statement released by the Illinois State Police, it’s stated, “Illinois State Police will work with local law enforcement to enforce this order but adhering to the order will save lives and it is the responsibility of every Illinoisan to do their part.”[iv] In other locales, like Harris County, Texas, it’s been said that failing to wear masks in public could result in a $1,000 fine,[v] an order that’s being challenged in court for being unconstitutional.[vi]

But as widespread advice to wear masks proliferates the U.S. — and a police state to enforce their wearing grows — the question remains: does wearing a mask really prevent the spread of COVID-19?

Face Masks Led to ‘No Significant Reduction’ in Virus Transmission

The idea of wearing a face mask, according to the CDC, is not so much to protect the wearer, but rather to benefit the population overall. If you’re infected with COVID-19 and don’t have symptoms, the theory is that wearing a mask could prevent you from inadvertently infecting someone else when you’re out and about.[vii]

Studies, however, don’t bear this out. In a May 2020 systematic review published in Emerging Infectious Diseases — a journal published by the CDC — researchers identified 10 trials that reported estimates of the effectiveness of face masks in reducing cases of influenza in the community. “In pooled analysis,” they stated, “we found no significant reduction in influenza transmission with the use of face masks.”[viii]

This included a study of face mask use among pilgrims from Australia during the Hajj pilgrimage — no major difference in the risk of influenza infection was found between the mask wearers and non-mask wearers. Two studies in university settings were also included, looking into the effectiveness of face masks among student hall residents for five months.

“The overall reduction in ILI [influenza-like illness] or laboratory-confirmed influenza cases in the face mask group was not significant in either studies,” the researchers found.[ix]

Surgical Masks, Cotton Masks Ineffective at Filtering SARS-Cov-2

A study of four patients with COVID-19 led to similar results — that wearing masks does little to block SARS-Cov-2, the virus that causes COVID-19.[x] Researchers asked the patients to cough five times into a petri dish while wearing no mask, a surgical mask and then a cotton mask. They swabbed the inner and outer mask surfaces afterward, finding that while most swabs from the inner mask surfaces were negative for SARS-CoV-2, all swabs from the outer mask surfaces were positive.

This raises two important points. First, as the study noted, “Neither surgical nor cotton masks effectively filtered SARS-CoV-2 during coughs by infected patients.” Second, the fact that the outer surface was more contaminated highlights the problems that can occur if a person touches the outside of their mask — thereby contaminating their hands. It’s possible that air leakage around the edge of the mask allowed the outer mask to become contaminated, or that the small aerosols of SARS-CoV-2 were able to penetrate the masks.

Either way, “[t]hese observations support the importance of hand hygiene after touching the outer surface of masks,” according to the researchers, but the likelihood of the general public, including children, washing their hands every time they touch their mask is small. A 2010 study added that while some evidence suggests wearing masks or respirators when you’re ill may protect others, there is less evidence on mask wearing to prevent becoming infected, especially in real-world settings:

“In conclusion there remains a substantial gap in the scientific literature on the effectiveness of face masks to reduce transmission of influenza virus infection.

While there is some experimental evidence that masks should be able to reduce infectiousness under controlled conditions, there is less evidence on whether this translates to effectiveness in natural settings. There is little evidence to support the effectiveness of face masks to reduce the risk of infection.”[xi]

If COVID-19 Is Aerosolized, Surgical and Cotton Masks Ineffective

The idea of cloth face coverings preventing transmission was based on the idea that COVID-19 is primarily spread via large respiratory droplets. Research now suggests, however, that SARS-CoV-2 may remain suspended in aerosols for up to 16 hours.[xii]

It’s also been found that COVID-19 particles may be as small as 1 to 4 microns in size,[xiii] while surgical masks only protect against particles larger than 100 microns.[xiv],[xv] Again, surgical masks are intended to protect the wearer against large droplets or splashes of bodily fluids, while protecting others from the wearer’s respiratory emissions.

Even the CDC states that surgical masks do “not provide the wearer with a reliable level of protection from inhaling smaller airborne particles and is not considered respiratory protection.”[xvi] On the contrary, an N95 respirator is a type of mask with a tight-fitting face seal designed for health care workers who may be exposed to hazardous small particle aerosols.

In the case of respiratory virus and influenza, rates of infection were double among those wearing surgical masks compared to those wearing N95 respirators.[xvii] This suggests N95 respirators offer some protection, but not only are they in short supply, they’re only typically worn by health care providers performing certain high-risk procedures.

Wearing a Mask May Increase Virus Transmission, Cause Adverse Effects

The Emerging Infectious Diseases review pointed out that in lower-income settings reusable cloth masks are more likely to be used than disposable medical masks due to cost and availability. Indeed, reusable cloth masks are what’s being promoted across much of the U.S., even though research is scarce into the use of such masks, and wearing them the “wrong” way could backfire.

“Proper use of face masks is essential because improper use might increase the risk for transmission,” according to the study.[xviii] Speaking with Forbes, Dr. Eli Perencevich, a professor of medicine and epidemiology at the University of Iowa’s College of Medicine, agreed:

“The average healthy person does not need to have a mask, and they shouldn’t be wearing masks … There’s no evidence that wearing masks on healthy people will protect them. They wear them incorrectly, and they can increase the risk of infection because they’re touching their face more often.”[xix] 

“Wearing a mask is tricky,” he added, “because it can create a false sense of security. If you don’t wash your hands before you take off the mask and after you take off your mask, you could increase your risk.”[xx] There are some risks inherent to wearing a mask, as well, such as hypoxia.

One study found a decrease in the oxygen saturation of arterial pulsations (SpO2) and a slight increase in pulse rates among surgeons wearing a surgical mask, and the decrease was more prominent in surgeons over the age of 35.[xxi] The risks may be higher for N95 respirators, which may impede gaseous exchange and increase workload on the metabolic system, particularly in pregnant health care workers.

“The benefits of using N95 mask to prevent serious emerging infectious diseases should be weighed against potential respiratory consequences associated with extended N95 respirator usage,” researchers concluded.[xxii] Headaches,[xxiii] dizziness, shortness of breath and even reduced working efficiency and ability to make correct decisions are also common following prolonged usage of N95 respirators.[xxiv]

Even WHO Warns of Mask Risks

The World Health Organization (WHO), while recommending that people with symptoms wear a medical mask, states, “the wide use of masks by healthy people in the community setting is not supported by current evidence and carries uncertainties and critical risks.” They also warn that the following potential risks should be taken into account:[xxv]

·      Self-contamination that can occur by touching and reusing contaminated masks

·      Potential breathing difficulties, depending on type of mask used

·      False sense of security, leading to potentially less adherence to other preventive measures, such as physical distancing and hand hygiene

·      Diversion of mask supplies and consequent shortage of masks for health care workers

·      Diversion of resources from effective public health measures, such as hand hygiene 

The potential benefits of mask wearing become even more dubious when it comes to the cloth masks now being widely used across the U.S. In a 2015 study led by Raina MacIntyre at the University of New South Wales in Sydney, 1,607 health care workers in Vietnam were given either disposable medical masks or reusable cloth masks that could be washed at home at the end of the day.[xxvi]

Penetration of cloth masks by particles was almost 97%, compared to 44% for medical masks, and those who wore cloth masks were much more likely to be infected with a virus. The results were so poor that the study cautioned against the use of cloth masks in a health care setting, stating that moisture retention, reuse of cloth masks and poor filtration could increase infection risk, and researchers stated, “Further research is needed to inform the widespread use of cloth masks globally.”[xxvii]

“There's just not a lot of evidence for cloth masks in the community,” MacIntyre told New Scientist.[xxviii] In Finland, meanwhile, COVID-19 restrictions are being eased without the recommendation for widespread mask wearing. Since research findings into the benefits of face masks vary, the government intends to conduct a detailed study before recommending that the general population wear them.[xxix]

While the evidence for wearing masks remains scarce, opposition to mask wearing is mounting among Americans, with reasons ranging from not believing it’s necessary to feeling it’s unjust for the government to force people to wear a face covering.[xxx] Such moral and ethical controversies are likely to continue, especially since masks may fail to protect people from illness as intended.



[ii] U.S. CDC, Use of Cloth Face Coverings to Help Slow the Spread of COVID-19

[iii] Illinois Department of Public Health, Guidance on the Use of Masks by the General Public

[xi] Epidemiol Infect. 2010 Apr;138(4):449-56. doi: 10.1017/S0950268809991658. Epub 2010 Jan 22.

[xvii] Influenza Other Respir Viruses. 2011 May;5(3):170-9. doi: 10.1111/j.1750-2659.2011.00198.x. Epub 2011 Jan 27.

[xxiii] Acta Neurologica Scandinavica February 28, 2006

[xxiv] September 15, 2005

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