Face masks and other personal protective equipment (PPE) is still in short supply in the U.S., leading many people to reuse surgical masks or N95 respirators several times. In some cases, this may be safe — and may even be a good idea to help lighten burden of these shortages. At other times, putting on the same mask again may do more harm than good.
The Center for Disease Control and Prevention here in the U.S. has advised all Americans to wear some kind of face covering several weeks ago — including disposable surgical masks or cloth face coverings. N95 respirators are still the most effective, but they are also in short supply at hospitals where they are most needed, so people are being asked to donate unused N95 masks if they have them. People can now be seen wearing everything from surgical masks to scarves to the collar of their own shirt pulled up over their noses out in public these days.
Beyond N95s, the guidance changes significantly. While the CDC now advises everyone to wear some kind of face covering while they're out, the World Health Organization still says that masks only need to be worn by a person who suspects they might be sick and cannot avoid coming into contact with other people. Studies have shown that cloth masks can retain moisture from the breath while filtering out far fewer particles than disposable masks, making them potentially dangerous if used improperly.
In the context of public health, face masks are a deep rabbit hole to go down, with a lot of conflicting information and hard arguments to make. The most important things to remember are to wash your hands often and avoid touching your mask, as it could easily serve as a vector for the virus on its own. It's also important to remember that masks do not replace social distancing, which remains the most important factor in slowing the spread of COVID-19.
With that out of the way, here are some helpful tips from health experts on how to use masks safely and effectively to protect your loved ones and your community from the coronavirus pandemic.
Given the shortage of N95 respirators during this global outbreak of #COVID19, it’s important to understand the difference between N95 respirators and surgical masks, and how both are intended to protect healthcare workers. Learn more from @NIOSH: https://t.co/rGGoSYDYUy. pic.twitter.com/8zuKKeiRlU— CDC (@CDCgov) May 2, 2020
N95 respirator masks remain the most effective for preventing the spread of COVID-19, but they are also in extremely short supply. The CDC has issued guidance allowing health care workers to reuse them safely between shifts when needed, though this is far from ideal.
Americans with unused N95s are still urged to donate them to a local hospital if possible. Even if that particular facility is not running low, many hospitals are now working together to share resources through this crisis.
If you have a used N95 and want to reuse it, there are some circumstances where it may be all right. The CDC recommends that N95s not be shared between multiple users, so whoever used it first should be the only person to put it on. Users should wash their hands before putting the mask on or taking it of — or be wearing clean gloves.
Between uses, an N95 mask should be hung up where it can dry, not allowed to touch any other surfaces, and covered with a paper bag or other breathable protection. However, the CDC stresses that even the best-cared for mask will become more danger than protection quickly. A mask should be immediately discarded if it comes into contact with blood, saliva or nasal secretions, any aerosol-generating procedures or even unwashed hands. The agency even recommends throwing away the mask if it has been worn into a hospital with confirmed COVID-19 cases.
To extend the lifespan of an N95 respirator, a cleanable face shield may help.
Disposable Surgical Masks
The WHO has also circulated several videos and infographics online, urging people to use masks carefully and not reuse surgical masks if at all possible. Lucy Wilson, chair of the department of emergency health services at the University of Maryland Baltimore County, told Huffington Post that, ideally, surgical masks should not be reused.
"The goal is not to reuse masks. It's really a stopgap measure for the mask shortage that we're having, but it's not the best practice," Wilson said. "The best practice would be single-use."
Experts say these masks should be thrown away as soon as they are visibly damp from use, as it is now retaining saliva from the breath which may carry the virus.
Of course, with supplies dwindling, sometimes masks must be reused in extreme circumstances. There is guidance some for that as well — both the CDC and the WHO have released explanations and infographics to show how to handle your mask safely, without turning it into a potential infection vector itself. If a mask must be reused, it should be put on and taken off as carefully as possible, with clean hands, and users should never touch the front of the mask. If someone touches the inside of the mask, it is no longer safe to wear.
"Do not touch the inside of that mask, because then you are contaminating the inside of the mask," Wilson said. "And if you put it back on, then you're just putting that directly on your mucous membranes. You could self-contaminate."
When you wear a cloth face covering, you help protect those around you from #COVID19. Help keep each other safe by continuing to properly wear cloth face coverings every time, the entire time you’re in public. Learn more: https://t.co/lxWMe4NUBD. pic.twitter.com/42bOU3Vuuh— CDC (@CDCgov) May 4, 2020
As for cloth masks, they must be used sparingly and washed frequently. The CDC now advises cloth face coverings for essential trips out such as grocery shopping, but they are not suitable for extended periods of time. A 2015 study published by the medical journal BJM Open concluded: "A homemade mask should only be considered as a last resort to prevent droplet transmission from infected individuals, but it would be better than no protection."
The study noted that cloth masks retain far more moisture than disposable ones, which could lead to "an increased risk of infection," since the wearer is being consistently exposed to the germs in that moisture. At the same time, cloth masks filter far fewer particles from the air, so the protection for the wearer and the people around them is not as great. Surgical masks are likely three times more effective against spreading viruses than cloth ones.
Dr. Hilary Lin told Huffington Post that some cloth face coverings could be used to extend the lives of respirators or surgical masks. Lin noted that wearing a scarf or other cloth layer over a mask would add a layer of filtration and protect the mask itself from germs, debris and fluids.
"If you're protecting others from yourself, or yourself from others, you can maintain the cleanliness of the mask by putting something over it," she said. "Scarves and other materials are terrible as filtration barriers, but if you put it over the mask, then you create more of a barrier and also you protect your mask from getting contaminated by droplets."
Washing cloth masks
Wearing a cloth face covering CORRECTLY can help prevent the spread of #COVID19 to others. When you go out on essential trips, follow these “do’s”. If you have a child, remember those under age 2 should not wear a face covering. See https://t.co/lxWMe4NUBD. pic.twitter.com/Vz7rMt7O52— CDC (@CDCgov) April 30, 2020
The upside to cloth masks, however, is that they are more reusable and easier to get a hold of during the coronavirus pandemic. However, users should follow all the precautions they would use with a surgical mask when putting on and taking off its cloth counterpart.
Cloth masks must be worn for as short a time as possible, and should be definitely be machine-washed after every single use.The masks should also be allowed to dry fully before they are put back on — preferably in a place where they cannot pick up contaminants from other laundry or surfaces. Again, experts say that hang-drying in a paper bag is a great option here.
When to Stop
Growing evidence suggests #COVID19 can spread before people show symptoms (pre-symptomatic) and from people who have #coronavirus but never show symptoms (asymptomatic).— CDC (@CDCgov) April 27, 2020
Cloth face coverings help prevent spread of COVID-19 in these situations.
See Q&A: https://t.co/vuYx19NZPE. pic.twitter.com/RE9K3kZmYR
While some of these strategies may extend the life of a mask, experts stress the importance of knowing when to let the mask go. Even the most well-cared for mask will eventually become more of a danger than a protection. Lin said that a mask should definitely be thrown away when it shows "visible dirt or damage."
The WHO maintains its recommendation to throw away surgical masks as soon as they are damp. Wilson echoed this advice, adding that people should not be discouraged if they lose their only mask and cannot get another one.
"Masks are just one part of the prevention," she said. "The most important part is hand-washing. Unless you are within 6 feet of someone who is actively coughing, your risk of infection is really from inadvertently touching something that’s contaminated in the environment."