The Science

There should be universal wearing of masks”
Dr. Anthony Fauci

Two months after the coronavirus pandemic officially began, two hair stylists in Missouri were infected with COVID-19. They didn’t know it, at least at first. So, they continued to work. One had symptoms and might have passed on the infection to the other. By the eighth day of infection, the first left work to recover and the other began to self-isolate.

In that eight-day span, from when the symptoms started until they stayed at home to recuperate, the stylists had worked, up close and personal, with 139 clients. With that many people around and with a virus that has proved to be awfully contagious, that hair salon could have become a COVID-19 superspreader factory.

But it didn’t. 

According to a case study by the CDC, that’s because everybody—the stylists, their co-workers, and the clients—wore masks, as recommended at the time by the city of Springfield, Missouri. Among the 67 clients that were tested after their encounter with the stylists, all of them were negative for the coronavirus. 

The reason why? Masks.

The coronavirus pandemic has altered countless lives across the globe, and reverberations of the COVID-19 virus and its worldwide spread could reverberate for the next several generations. For months, global experts and doctors have said that the act of wearing a mask to protect yourself and others is an important way to get through the pandemic—to get back to a normal life, to see the family members we’ve missed, to restart the global economy, and to prevent more deaths. Wearing a mask has been the message over and over again for the past several months. 

There should be universal wearing of masks,” Dr. Anthony Fauci, the face of the Trump administration’s coronavirus response team, told ABC News in August. “

… [The] universal wearing of masks is one of five or six things that are very important in preventing the upsurge in infection and in turning around the infections that we are seeing surge.”

This article will examine, in depth, whether they’re right. 

To answer that question, we’ve gone in search of every piece of evidence that addresses how masks perform in a community environment during the pandemic. We’ll present it all: lab studies, research projects that have observed people in real life, and meta-analyses surveying the dozens of mask studies that have been produced since the pandemic began. And we’ll hold nothing back—we’ve tried to be comprehensive and share the good, the bad, and the ugly.

Coming to our own conclusions, we’ve tried to review the evidence as thoroughly as possible—and without bias. Our expectations certainly were influenced by the headlines that dominate the news and social media right now, but we tried as best we could to hold up those assumptions to the greatest possible scrutiny and see what the evidence really, truly says. We’ll share the evidence and our conclusions with you—why we think what we think, what we know, and what we don’t—so that you can decide for yourself what you think the evidence is saying.

Our reading is that the science is fairly definitive in support of mask wearing under the right conditions. If you’d like to go deeper, our research page contains all the research evidence we’ve been able to find on this subject, with notes and links so you can be as informed as you’d like to be.

Certainly, not every scientist and researcher agrees that masks are the solution to the pandemic problem, and when it began, even the U.S. surgeon general said to avoid wearing them. As Jerome Adams said at the time,  “You can increase your risk of getting it by wearing a mask if you are not a healthcare provider. Folks who don’t know how to wear them properly tend to touch their faces a lot and actually can increase the spread of coronavirus.”

But the evidence has become clearer and clearer and the surgeon general has since recanted his skepticism. The hard figures and numbers below show why he and other experts are mostly now in agreement that masks are a necessity. 

Evidence gathered around the world overwhelmingly supports wearing masks. For the past several months, studies have shown that if people wear masks that fit snugly across the face and wear them before they actually get sick, COVID-19 transmissions decrease. That research has shown that by wearing those face coverings, the respiratory droplets that can infect others are not released into the air, that mask mandates work, that children should be masked, and that even those who are knowingly infected by the coronavirus can keep others safe from infection by wearing a face covering.

If people wear masks, COVID-19 transmissions decrease. 

At the end of this article, we’ll unpack all the evidence that shows how and why masks work, we’ll explain how to wear a mask properly, and why should children should wear them as well.

But first, to evaluate whether and how well masks work, we need to make sure we understand the disease—most importantly, how it’s transmitted.

How does coronavirus spread?

Since the novel coronavirus first appeared in Wuhan, China at the beginning of 2020, the symptoms have included a fever, chills, coughing, a shortness of breath, and a loss of taste or smell. Long-term symptoms, which also includes fatigue, could linger for months afterward. The Cleveland Clinic calls those patients “long-haulers” or “long-termers.” 

The transmission of the virus mostly occurs from person-to-person contact through respiratory droplets from an infected person’s mouth or nose. An infection can also occur when smaller aerosol particles potentially hang in the air for hours and infect a person passing through that airspace.

If a person feels they might be infected, the Centers for Disease Control recommends that you stay home unless you need medical care, take care of yourself with rest and hydration, and avoid getting close to other people. And you should wear a mask, the CDC said.

But a key point throughout is that people can transmit the virus before they have symptoms—before they know they’re sick or infected. So wearing a mask isn’t just for those who have been infected. It’s for those who want to keep from getting themselves or others sick. 

A lot of this has been known since fairly early on in the pandemic, but it’s only been more recent that evidence has emerged that the coronavirus can linger in the air well after an infected person has left. Despite that knowledge, in the first few months after the coronavirus appeared in China, some officials proclaimed that people shouldn’t be wearing masks. This early recommendation was partly based on not knowing that the virus can linger. More so, it seems to be because scientists were primarily thinking about how masks are used in a medical setting. 

But soon, evidence emerged that masks behaved differently in a community setting and could be an important preventative measure. By April 2020, the World Health Organization and the CDC were clear: People need to wear masks, because they ARE effective in slowing down the spread of the coronavirus.

Sometimes, they stop the virus altogether. As the CDC wrote, “Consistent and correct use of cloth face coverings is recommended to reduce the spread of SARS-CoV-2.”

In the case of those two Missouri stylists, it certainly did. 

Do masks actually work?

“Public mask wearing is most effective at stopping the spread of the virus when compliance is high. The decreased transmissibility could substantially reduce the death toll and economic impact while the cost of the intervention is low,” wrote researchers in a non-peer reviewed study titled Face Masks Against COVID-19: An Evidence Review. “Thus we recommend the adoption of public cloth mask wearing, as an effective form of source control, in conjunction with existing hygiene, distancing, and contact tracing strategies. We recommend that public officials and governments strongly encourage the use of widespread face masks in public, including the use of appropriate regulation.”

But why should people wear masks, who should be wearing them, and how should they do so? And could the simple act of donning a face covering actually bring an end to the pandemic that has caused more than 1 million global deaths and innumerable amounts of sickness, economic and social turmoil, and personal sadness?

Most of the studies that have been done on masks since the beginning of 2020—whether they’re a randomized control trial (RCT), an observational study, or a meta-analysis of previously published literature—have shown solid support to indicate that wearing them during the pandemic will slow the spread of the coronavirus.

The RCTs or studies that have been performed in a lab have shown that many masks help contain the respiratory droplets that can cause transmission. 

A Duke University study released in September 2020 studied a variety of face masks, mostly of the homemade or easy-to-procure variety, to determine which offered the best protection. The researchers’ aim was to figure out which masks effectively reduced the amount of respiratory droplets that were released into the air during regular speech.

To do so, researchers used a cell phone camera to record a person who stood in a dark room, wore a mask, and spoke in the direction of an expanded laser beam. A “simple computer algorithm” then was used to count the number of respiratory droplets that emerged from the person’s mouth and escaped the mask.   

As the researchers wrote, “Even from these limited demonstration studies, important general characteristics can be extracted by performing a relative comparison between different face masks and their transmission of droplets.”

They tested 14 masks or commonly available mask alternatives. More from the study:

“For reference, we recorded control trials where the speaker wore no protective mask or covering. Each test was performed with the same protocol. The camera was used to record a video of approximately 40 [seconds] length to record droplets emitted while speaking. The first 10 [seconds] of the video serve as baseline. In the next 10 s, the mask wearer repeated the sentence “Stay healthy, people” five times (speech), after which the camera continued to record for an additional 20 s (observation). For each mask and for the control trial, this protocol was repeated 10 times.”

These were the masks the researchers used. 

The results showed that the N95 mask released the fewest number of droplets. That was followed by a surgical mask and then various cotton coverings. A ventilated N95, which allows air to be expelled through the mask and into the atmosphere and is not recommended by the CDC, was in the middle of the pack. The masks deemed the worst performing were a bandana and a neck gaiter. In fact, the gaiter performed even worse than not wearing a mask at all, because it “disperse[d] the largest droplets into a multitude of smaller droplets.”

As the study’s authors wrote regarding the gaiter, “Considering that smaller particles are airborne longer than large droplets (larger droplets sink faster), the use of such a mask might be counterproductive.”

Though the demonstration was simplistic and therefore might be somewhat limited—it’s also unclear how accurate the laser and/or the algorithm were—it still provides a solid roadmap for those people who are trying to balance effective masks with their own comfort.

Another randomized control trial from November that studied the effectiveness of N95 masks, cloth masks, double- and single-layer neck gaiters, and face shields when a cough simulator spread aerosols into the room showed that the single-layer gaiter was much less effective than the other masks and the face shield was basically pointless. According to this medrxiv study, the N95 mask blocked 95% of particles and the cloth face mask blocked 51%. The double-layer neck gaiter stopped 60% of articles, while the single-layer only blocked 47%. The face shield only blocked 2%. 

A study from Thorax, a peer-reviewed journal that specializes in respiratory medicine, also reviewed the effectiveness of different kinds of face coverings. Most reusable masks have one or two layers, compared to the three layers in a surgical mask. Researchers used LED lights and high-speed cameras to measure the droplets and aerosols that were released when a volunteer spoke, sneezed, and coughed. Only one volunteer was used—this was a limitation of the study since different people can have different droplet patterns—and the research showed that masks most likely reduce virus transmission but that “masks are not a replacement for physical distancing measures.”

In April, Nature published a study that showed surgical face masks “significantly reduced detection” of influenza respiratory droplets and coronavirus aerosols while also seeing a “reduced detection” of coronavirus respiratory droplets. The researchers screened 246 individuals who provided exhaled breath samples. Nasal and throat swabs tested for viral shedding. According to the study, “Our results indicate that surgical face masks could prevent transmission of human coronaviruses and influenza viruses from symptomatic individuals.”

In a letter to the New England Journal of Medicine in April, three researchers described how they used a laser, a light sheet, and a cardboard box to determine the number of droplets that were produced by a speaker who said the words “stay healthy.” The highest number of droplets that were produced occurred when the speaker said the “th” part of “healthy,” and more droplets were recorded the louder the person talked. But when a damp washcloth, acting as a mask, was placed over the mouth of the speaker, there was a decrease in those droplets.

In June, the International Journal of Infectious Diseases studied four randomized clinical trials of masks and respirators. Its data showed that infected children did not transmit seasonal coronaviruses to their mask-wearing parents. Meanwhile, healthcare workers wearing an N95 had lower rates of infections than those who wore surgical masks, though the difference was not significant. 

Though not all face coverings are effective, surgical masks, cloth masks, and N95 masks are the best fits. Surgical masks are the disposable masks that are loose fitting, and they protect the user’s mouth and nose from other people’s droplets while also filtering out larger aerosol particles. They also might protect other people from your saliva and respiratory droplets. The polypropylene layer in surgical masks holds an electrostatic charge that basically traps incoming and outgoing droplets because of static electricity (or static cling). But a study published in Physics of Fluids in December showed that used surgical masks should not be worn, as the efficacy of those masks can drop from about 65% to 25%. “It is natural to think that wearing a mask, no matter new or old, should always be better than nothing,” study author Jinxiang Xi told the New York PostOur results show that this belief is only true for particles larger than 5 micrometers, but not for fine particles smaller than 2.5 micrometers.”

N95s are the respirator masks worn by healthcare professionals, and they’re designed to block 95% of the small particles. The easiest type of mask for a layperson to procure in the pandemic’s early days was a cloth mask, which traps the droplets expelled by a user and which protects the people around you even if you have the coronavirus but don’t know it.

Yet, other researchers found in September 2020 that there wasn’t a significant difference between three-layer cotton masks and surgical masks in droplet prevention. In a Science of The Total Environment study, more than 200 adult volunteers who had an influenza infection or a suspected case of COVID-19 wore a medical mask or a triple-layer cotton mask in either a bedroom or in a car with air conditioning. The test results showed that a cotton mask had an 86.4% percent filtration efficiency for particles with a size range of 20-1000 nanometers (the novel coronavirus has been measured between 60-140 nanometers). Filtration efficiency represents “the capacity of holding particles and viruses in the air,” and a 3M medical mask had a 99.9% percent filtration efficiency. The study concluded that “the cotton mask could be a potential substitute for [a] medical mask for respiratory infection person in [a] microenvironment with air conditioning.”

In an Aerosol Science and Technology study in which researchers used 44 samples of household materials and several different kinds of masks to determine how well homemade face coverings could filter out exhaled respiratory particles that ranged from 30nm-10µm, surgical masks weren’t as effective for smaller particles when compared to synthetic fibers like woven and jersey material and natural fibers like cotton and silk. As researchers noted, “the more layers and the tighter the weave resulted in the best efficiency.” The study also showed that more flexible fabrics—like terrycloth, felt, and velourperformed as well or better than surgical masks for smaller particles.

Researchers in this ACS Publications study also studied different kinds of fabric. In this June paper, 32 materials that could be used for cloth masks were tested for filtration efficiency, differential pressure, quality factor, and construction parameters. After testing samples made of cotton, synthetic, synthetic blends, synthetic/cotton blends, and wool, researchers determined that the best samples were “woven 100% cotton with high to moderate yarn counts” (though the N95 was still more effective than any of the others). 

Most observational studies on mask wearing also showed a positive effect in lowering coronavirus transmission rates. The Missouri hair stylist case was one such study. 

Early in the pandemic, researchers in China conducted a large systematic review of 124 families to determine if wearing a mask while in the same household as an infected person could keep the mask-wearer safe. To do that, researchers studied members of the same household who were in contact four days before and more than 24 hours after the virus-carrier was infected. According to BMJ Global Health, 77% of those who wore masks in the household were not subsequently infected by the original carrier. But that’s only if masks were worn by the infected person and the rest of the household before the symptoms emerged. The researchers wrote, “The study confirms the highest risk of transmission prior to symptom onset, and provides the first evidence of the effectiveness of mask use, disinfection, and social distancing in preventing COVID-19 … This further supports universal face mask use, and also provides guidance on risk reduction for families living with someone in quarantine or isolation, and families of health workers, who may face ongoing risk.”

The early adoption of mask wearing led to promising results for the countries that have either mandated it or that have citizens who have voluntarily done so.

According to a Journal of Infection study from April 2020, Hong Kong had face mask compliance of nearly 97% (to get that number, researchers counted the number of people in public who were not wearing a mask during the morning commute on three consecutive days). Hong Kong citizens began wearing masks early in the pandemic. As a result, Hong Kong’s coronavirus rates were exponentially better than those in the U.S., Singapore, Germany, France, and the U.K. The study’s conclusion was that, “Community-wide mask wearing may contribute to the control of COVID-19 by reducing the amount of emission of infected saliva and respiratory droplets from individuals with subclinical or mild COVID-19.”

Unlike many Western nations, Hong Kong residents have historically conformed to wearing masks during times of sickness, and according to the study, that precedent was one reason why Hong Kong rates were so much lower than other countries whose citizens weren’t as eager to wear masks.

As the BBC wrote in May 2020, “In some parts of Asia everyone wears a mask by default—it is seen as safer and more considerate. In mainland China, Hong Kong, Japan, South Korea, Thailand, and Taiwan, the broad assumption is that anyone could be a carrier of the virus, even healthy people. So in the spirit of solidarity, you need to protect others from yourself.” It’s also worth noting that none of those nations are among the top-45 countries for most coronavirus cases in the world. 

In June, a Health Affairs observational study that looked at 15 states (and Washington D.C.) that mandated face masks for people out in public showed that the daily case rate decreased by 2% in the three weeks after the face coverings became mandatory. The predictive model also suggested that the mask mandates could have prevented between 230,000-450,000 new coronavirus cases by May 2020.

A study completed by the IZA Institute of Labor Economics—which used a control method that studied a combination of groups to look at the spread of the coronavirus in Germany—showed that masks reduced coronavirus cases between 2%-13%, depending on the regions the researcher analyzed, in the 10 days after they became mandatory in April 2020. The study concluded that masks, across all of the regions studied, reduced “the daily growth rate of reported infections by around 40%.”

In a Canadian study via the National Bureau of Economic Research that came out in October 2020—a few weeks after mask mandates were implemented—researchers, utilizing Google mobility data to partially account for behavioral responses, found that there was a 25% reduction in new COVID-19 cases.  

More recently, the CDC announced in October that Arizona coronavirus cases dropped by 75% after the state instituted a mask mandate coupled with other preventative measures. Based on that study, the CDC concluded that “widespread implementation and enforcement of sustained community mitigation measures, including mask wearing, informed by state and local officials’ continual data monitoring and collaboration can help prevent transmission of SARS-CoV-2 and decrease the numbers of COVID-19 cases.” 

In November, the CDC released its findings on the Kansas state mandate that was instituted in July 2020. The study showed that the counties that enforced the mandate (24 out of 105 counties) saw a net decrease of 6% of COVID-19 cases in their seven-day rolling average. For the 77% of counties that opted out of the mandate, they saw an increase of 100% in cases in that seven-day rolling average. The CDC concluded, “The decrease in cases among mandated counties and the continued increase in cases in nonmandated counties adds to the evidence supporting the importance of wearing masks and implementing policies requiring their use to mitigate the spread of SARS-CoV-2.” 

By late November, 37 states had implemented a mask mandate, and a study from the University of Utah’s business school showed that it could help the nation’s economy. Though the study was still awaiting peer review and publication, researchers studied consumer mobility, credit card spending, and COVID-19 case data from all 3,142 U.S. counties. The researchers found that people were 51% more likely to go to a store (and to spend money) if everyone inside was wearing a mask. But if only half the people inside were wearing a face covering, Utahns would be 13% less likely to enter. If people felt safe, researchers said, they were more likely to increase their mobility and their consumer spending. 

In a study released in January 2021, researchers used a cross-sectional online study of more than 370,000 surveys to determine whether the use of masks outside the home cut down on the community spread of the virus. The study compared people’s mask-wearing habits to the public data on COVID-19, and it showed that mask usage was higher among women and non-white ethnic group, older people, and people with lower income. Interestingly, the researchers said that a 10% in increase in mask usage resulted in three times better transmission control in the community. 

One reason wearing masks is helpful is because it prevents people from touching their noses and mouths, which is one way the coronavirus can spread, and because it literally reminds people that they’re in the middle of a serious pandemic and that they need to be careful when in the outside world. The combination of mask-wearing and hand hygiene lowered the risk, according to a Journal of Infection study.

As the authors wrote:

“Masking is a continuous form of protection to stop the spreading of saliva and respiratory droplets to others or from others, and to the environment or from the environment to the susceptible by hands through touching of nose, mouth and eye. Touching nose and mouth is a subconscious behavior. Hand hygiene is always the cornerstone to prevent transmission of COVID-19 but it is a one-off discontinuous process where hand contamination may occur easily between each alcoholic handrubbing or hand washing. … Studies have also shown that wearing a mask with frequent hand hygiene significantly reduced transmission of seasonal influenza virus in the community setting. But once the effect of the use of surgical mask was removed, the effect of hand hygiene became insignificant.”

Even if a person catches the coronavirus while wearing a mask, a perspective from the Journal of General Internal Medicine has shown that the virus’ load is diminished. That leads to more mild or asymptomatic cases. As one of the authors said in a University of California-San Francisco press release, “The more virus you get into your body, the more sick you are likely to get … Masks can prevent many infections altogether, as was seen in health care workers when we moved to universal masking. We’re also saying that masks, which filter out a majority of viral particles, can lead to a less severe infection if you do get one. If you get infected, but have no symptoms—that’s the best way you can ever get a virus.”

Those studies that used meta-analysis and surveys to come to a conclusion on the effectiveness of masks also mostly showed positive results for those who wear face coverings. 

A Lancet study released in June 2020 that reviewed 172 observational studies from 16 countries and six continents showed that “face mask use could result in a large reduction in risk of infection.” The studies that were reviewed included cases of COVID-19, SARS, and MERS, and the data suggested that “wearing face masks protects people (both health-care workers and the general public) against infection by these coronaviruses … However, none of these interventions afforded complete protection from infection, and their optimum role might need risk assessment and several contextual considerations.”

Healthcare workers and other adults aren’t the only ones who need to wear masks. The CDC recommends them for children, as well.

The CDC noted that it might be challenging to make sure young children, those in elementary school, and those with special educational or healthcare needs are wearing masks. But in an European Journal of Pediatrics article published in August 2020, the authors noted that masking children is vital. “Preparing the healthy child to use face masks is strongly needed,” the authors wrote. “To obtain maximal compliance, reasons for mask wearing without attempts of removing must be clearly explained. Moreover, [a] child’s will must not be forced. Conclusion: On the basis of clinical findings, we think that the universal use of facial masks seems necessary when people have to go out in their everyday lives. In addition to the availability of masks of different sizes capable of adapting perfectly to the face, it is necessary that the use of masks in children is preceded by a strong parental work and school lessons on this issue and other hygiene topics with the main aim to obtain child cooperation.”

Masks aren’t the only way to protect yourself during the pandemic. Social distancing and disinfecting the areas around you are also important. But when those two precautions aren’t possible, masks are most likely what will keep you safe.

Not all masks, though, are created equally.

A literature review in Cureus on a variety of studies, though, showed that cloth masks might have “limited inward protection” in healthcare settings because the viral exposure could be high. But researchers said that they could be beneficial in either low-risk settings or in the general public. For healthcare workers, N95 respirators used continuously during a shift were the most beneficial. 

A systematic review of 19 randomized controlled clinical trials by the International Journal of Nursing Studies showed that medical masks were ineffective and cloth masks were even less so for healthcare workers but that they were important for community use. The studies showed that mask-wearing in the community was effective with or without hand hygiene (though both actions together were even more protective), but in a healthcare setting, especially during high-risk procedures, the continued use of a respirator (an N95 mask) is what keeps a worker safe. Otherwise, a healthcare worker who takes off their N95 during their shift is in danger of being infected by aerosol transmission. Wrote the authors of the study: “In summary, the evidence is consistent that a respirator must be worn throughout the shift to be protective. Targeted use of respirators only when doing high risk procedures and medical mask use is not protective.”

Another study in Gastrointestinal Endoscopy in September showed that N95 masks should be limited to high-risk scenarios to help combat the shortage of PPE during the pandemic. The study researched 15 cited articles and determined that surgical masks “are not inferior compared with N95 respirators in terms of protective efficacy among healthcare workers.”

Not all the research agrees with the findings that people who wear masks are effectively fighting the coronavirus. However, those studies that show weak evidence for masks tend to also show that it’s the circumstances of mask use that’s rendering them ineffective.

In one study from the Journal of Applied Fluid Mechanics, researchers showed that if the mask doesn’t fit properly, “airflow containing virus-carrying droplets leak into or out of the mask unfiltered.” That’s why a tight-fitting mask is “of paramount importance.” According to the study’s authors, who used 2-D geometry and “commercial  computational fluid dynamics software” to research their findings in this RCT, self-made masks and surgical masks are not suitable “for filtering out the majority of exhaled droplets” because the gaps between the face and the masks will allow particles to escape. 

In a European Journal of Medical Research study from August 2020 that looked at “an extensive query” of data regarding masks in the community to prevent the spread of COVID-19, the authors found “only weak evidence for wearing a face mask as an efficient hygienic tool to prevent the spread of a viral infection.” The authors did find reason to determine that the use of masks worn over the nose and mouth can offer “relevant protection” in close-contact situations by “limiting pathogen-containing aerosol and liquid droplet dissemination.” Overall, the study found that face coverings only provide limited self-protection and it’s only when the masks are properly used that they could possibly be effective. But the researchers claimed that masks also provide more risks to people who are physically or psychologically adverse to wearing them.

Furthermore, a July 2020 study in Canadian Family Physician concluded that wearing masks in the community did not reduce the risk of transmitting influenza or other viral respiratory viruses. Researchers studied a number of systematic reviews and randomized clinical trials, and they wrote, “This systematic review found limited evidence that the use of masks might reduce the risk of viral respiratory infections. In the community setting, a possible reduced risk of influenza-like illness was found among mask users. In health care workers, the results show no difference between N95 masks and surgical masks on the risk of confirmed influenza or other confirmed viral respiratory infections, although possible benefits from N95 masks were found for preventing influenza-like illness or other clinical respiratory infections.” This study, though, did not have data for any COVID-19 mask research.

It was likely similar evidence, showing that medical masks are not completely effective in a healthcare setting that originally inspired medical officials to warn people off masks. Aside from interviews where he said not wear a mask, U.S. Surgeon General Adams also tweeted in February that people should “STOP BUYING MASKS” and that “they are NOT effective in preventing general public from catching #Coronavirus.”

A study in the Annals of Internal Medicine in November 2020 showed that mask-wearing in a Danish community that had modest infection rates with “some degrees of social distancing” did not reduce the coronavirus infection rate by more than 50%. In a randomized control study in Denmark that took place in April and May of 2020, about half of the nearly 5,000 people who participated wore masks when they were outside their home. Though the study’s findings offered evidence that mask-wearers are more protected in a setting where others are not wearing masks and where some social distancing measure are in effective, it was still difficult to determine whether the mask usage was the deciding variable. 

On the whole, however, our judgment is that the vast majority of the evidence indicates that masks work well for people not in a healthcare setting—with two caveats the masks have to fit and they have to be worn before people know they’re sick. Yes, there’s some evidence that masks don’t work—but the volume of that evidence is far outweighed by the evidence that they do, and most of the negative evidence can be explained by fit issues or by people only wearing the masks after symptoms appear.

Should some people avoid masks?

With hindsight, we know early statements against mask wearing continue to have ramifications months later, sowing confusion for citizens who were unsure how to keep themselves and others safe.

There are a couple of explanations for why this misinformation was so widespread in the early months of the disease’s arrival. Since COVID-19 is a novel coronavirus, experts and scientists simply didn’t know that what they were saying was incorrect. It was unclear how contagious the coronavirus is, and they didn’t realize people could be infected but also be fail to have symptoms—even if they developed them later. They knew masks for medical workers were in short supply, but they didn’t know much of anything else in the early going, as the information and research continued to change.

Those recommendations have changed since April, but not everybody is interested in wearing a mask. 

Some say they have medical exemptions that would preclude them from wearing one. People who have asthma or other respiratory difficulties could have trouble breathing while wearing a mask, and those who physically can’t put on or remove a mask (or who are incapicated) shouldn’t be expected to wear one. Children under the age of 2 should not wear a mask, and those who are in the hard of hearing and deaf communities also face more difficulties. But a gray area exists as well, particularly with those who have a sensory processing disorder, who have facial deformities that make wearing a mask uncomfortable or impossible, or who have a chronic pulmonary illness. 

But as the American Medical Association (AMA) notes, there is “a dearth of evidence as to what conditions may warrant a medical exemption from this requirement.” As such, some physicians have been put in an uncomfortable situation if patients want an exemption.

As the AMA recommended, “In evaluating an individual patient, clinicians should seek to balance appropriate accommodations with public health. It is crucial that individuals with disabilities be integrated in public spheres, a right that could be curtailed by withholding appropriate exemptions. But for many individuals seeking exemption, the risk of participating in public spheres during a pandemic may be high. For those with underlying pulmonary disease, if masking cannot be tolerated, sheltering in place is a reasonable and safe medical recommendation. … Clinicians have no obligation to provide a mask exemption to patients if it is not medically warranted. They do, however, have a clear obligation to address individual patients’ concerns, discuss appropriate alternatives, and offer clear recommendations for risk-reducing measures when patients are venturing into the public sphere.”

Yet medical professionals have to weigh these concerns against the evidence that not wearing a mask has major consequences. Even the surgeon general, who originally said to avoid mask-wearing, has begged people to ignore his earlier declarations.

“It’s important for people to understand that once upon a time we prescribed cigarettes for asthmatics, and leeches and cocaine and heroin for people as medical treatments. When we learn better, we do better,” Adams told Face the Nation in July.

A few days later, he told Fox News, “I’m pleading with your viewers. I’m begging you. Please understand that we are not trying to take away your freedoms when we say, ‘Wear a face covering.’”

Yet, some people still abhor the idea, they proclaim that their American freedoms override the notion that they should cover their face during a pandemic. It seems to us, however, that masks are a simple, cheap, effective way to fully enjoy every freedom. Wearing a mask, you have little need to avoid any activity you might want or need to pursue.

Which masks are effective?

For most of the pandemic, the CDC has recommended people over the age of 2 wear masks in public settings because they’re most likely “to reduce the spread of COVID-19 when they are widely used by people.”

To do that, masks need to be effective in keeping people safe, and people need to be aware of the efficacy of the face covering they’re wearing.

According to the research described above, the N95 mask, which filters out 95% of the particles (both big and small) in the air, is the most effective face covering. There have been shortages with N95s, though, and they’re not always easy to find, particularly if you’re not a healthcare worker. But avoid wearing an N95 with an exhalation valve or vent since the air you breathe out won’t be filtered and could have a better chance of infecting anybody near you.  

Surgical masks are also effective if they’re worn snugly across the face and if they cover both the nose and the mouth with minimal gaps around the rest of your face. The three layers on surgical masks, including the polypropylene layer that filters out particles via static cling, make those face coverings a good choice. 

Otherwise, multi-layered cotton masks can be effective, especially if they have a filter insert. 

People, though, should avoid using bandanas and neck gaiters as face coverings. In fact, one study showed that using a neck gaiter instead of a filtered mask is actually less effective than not wearing a mask at all.  

Yet to keep yourself protected, you actually know how to wear a mask. And most of us haven’t had medical training. So here’s your crash course in… 

How to Mask UP

The basics of mask-wearing can be mastered by anyone: 

  • Wash or sanitize your hands before you put it on your face; 
  • Place it over your nose and mouth and secure it under your chin; 
  • Keep it snugly fit against the sides of your face. 
  • When you want to take off the mask, handle it only by the ties or the ear loops and fold the outside corners together when it’s away from your face. 
  • If you have to adjust the mask while wearing it, make sure to wash your hands beforehand and afterward or to use a tissue or glove to keep the front of the mask as sanitized as possible. 

What you shouldn’t do

  • Don’t touch the front of your mask while it’s on, because you could potentially transfer virus particles that have landed on your face covering to your fingers, which you then could use to touch your nose or mouth. 
  • Don’t use a damaged mask, because it won’t effectively protect you from the coronavirus. 
  • Don’t use a dirty or wet mask, because moisture could make the masks begin to degrade. 
  • And don’t share your mask with others, because the virus could be more easily transferred between two people.

Since it’s not feasible for most people to discard masks after a single use, learning how to clean face coverings is vital information. With a generic cloth mask, you can wash it with your normal laundry, using regular detergent and a warm water setting. If you’d rather hand wash it, use hot, soapy water and scrub the mask for at least 20 seconds.

You can use a dryer or air dry it in direct sunlight. As long as the mask is completely dry before it’s worn again, it will continue to be effective. Cloth masks should be washed after every use.

If you’re using a disposable surgical mask, those can’t be laundered and they should be discarded when they become dirty or damaged. Experts, though, aren’t sure exactly how long you should wear a surgical mask before moving on to a fresh one, because no research has been published on the question.

Research published on the CDC website in September did show that N95s could be decontaminated up to three times for reuse before they need to be discarded. The study used four methods of cleaning—UV light, a dry heat of 158 degrees Fahrenheit, 70% ethanol, and vaporized hydrogen peroxide (VHP)—and afterward, the researchers measured the masks’ effectiveness after two hours of wear following the cleaning. The tests showed that there was no significant decrease in the masks’ performance after the first cleaning, but subsequent decontaminations showed more degradation. 

Perhaps the biggest mistake that people still make is wearing their masks over their mouths but not over their noses. Colin Furness, an infection control epidemiologist with the University of Toronto, said you might as well not wear a face covering at that point.

“I see it everywhere. I see it in grocery stores … I tend to see it, actually, [with] people wearing their masks outside,” Furness told Global News. “If someone’s got their nose peeking out, it’s really no different than not wearing a mask.”

And as the research shows, actually wearing a mask will help reduce COVID-19 transmission and eventually help return the world to its pre-2020 state. Yes, there are a few studies that show masks aren’t as effective as people would like. But the vast majority of the randomized control trials, the observational studies, and the meta-analysis draw a clear picture: Wearing a mask keeps us safer. 

Meanwhile, the coronavirus pandemic continues, infecting people with potentially lifelong complications and killing about 3% of those who get it. Cases are rising. More people are suffering. The sacrifice of wearing a mask in public is minimal when you really think about all the people who can be saved from this contagious virus. 

For “months and months … I have been on the airways, on the radio, on TV, begging people to wear masks,” Fauci said in September. 

Polls in October showed that more people support the idea of wearing masks and have begun to do so. Are you one of them?