Do You Need a Mask to Prevent Coronavirus?

With the number of cases of COVID-19 reported in the U.S. growing quickly, many are buying face masks.
 
But most healthy people who aren't caring for a sick person don't need to wear a face mask to prevent the illness, according to the Centers for Disease Control and Prevention and the World Health Organization. That includes plain, loose-fitting masks sometimes called surgical masks; tighter-fitting N95 respirators, which filter out 95 percent of airborne particles; and reusable face masks sometimes advertised as dust masks. 
 
The interest in masks is understandable, says William Schaffner, M.D., a professor of medicine in the division of infectious diseases at the Vanderbilt University School of Medicine in Nashville. But any benefit healthy people may get from wearing a mask is likely to be modest. In fact, if you’re not sick or taking care of people who are, wearing a mask comes with downsides. Here’s what you need to know.
 
On Feb. 29, the U.S. Surgeon General, Jerome M. Adams, M.D., warned Americans, via Twitter: “STOP BUYING MASKS!” He emphasized that masks don’t help prevent the spread of coronavirus in the general public. In the U.S., where there is a severe shortage of masks and other protective equipment, health officials want to ensure that the healthcare workers who are caring for the sick and getting the most benefit from masks are able to access them.
 
Other experts agree that there's little reason for the average person to wear a mask. “In the research that’s been done, we don’t see any benefit at the community level for wearing the mask,” says Amanda McClelland, M.P.H., a senior vice president at Vital Strategies, a public health organization that focuses on global health threats.
 
The N95 respirators are more snug but can be hard to fit properly. In fact, healthcare workers must take an annual test to prove that they can properly fit the device and create a full seal against leaks around the sides.
 
Additionally, face masks can be uncomfortable, so you may find yourself frequently adjusting the mask. Or you might take it off to eat or drink, then put it back on afterward. That defeats the purpose, McClelland says. “People contaminate themselves more by touching the mask and taking it on and off their face.”
 
Both surgical masks and N95 respirators are meant to be used only once and then thrown away—healthcare providers are supposed to use a new mask for every patient, in part because masks can be contaminated by germs during use. But consumers may be tempted to reuse them, possibly spreading the virus to other surfaces or items, says Aaron Glatt, M.D., chairman of medicine at Mount Sinai South Nassau and professor at the Icahn School of Medicine at Mount Sinai.
 
To prevent that possibility, healthcare workers clean their hands every time they remove a mask, Schaffner says.
 
As for those washable cloth masks you may see for sale, some evidence suggests that reusable masks aren’t the best option. A study in The BMJ in 2015 found that healthcare workers using cloth masks were more likely to be infected with respiratory diseases than those who used disposable surgical masks, even when workers washed them at the end of each of their shifts.
 
So Who Does Need a Mask?
People with symptoms that could be COVID-19—such as fever, cough, and shortness of breath—should wear a mask when they are around others, to limit the spread of infection, the CDC says. 
 
In addition, because the novel coronavirus is thought to spread mainly between people who have close contact—meaning within 6 feet—with each other, those who are caring for someone suspected of having COVID-19 should also consider wearing a mask, according to the CDC and WHO.
 
If you’re in one of those groups, it’s important to use masks properly. Wash your hands before putting the mask on, then try not to touch it. If you do, wash your hands again. Discard the mask as soon as it’s damp. To remove it, handle the elastic around your ears (not the front of the mask), throw it away immediately—either in a closed plastic bag or a bin with a lid—and wash your hands again. Don’t reuse the mask.
 
Healthcare workers should also use masks—preferably an N95—to protect themselves when caring for people suspected of having COVID-19, according to the CDC.
 
Some countries have advised broader mask use, and broader use "could be considered" if we're able to dramatically increase the available mask supply, according to an article published in the Lancet Respiratory Medicine journal on March 20. In China, for example, authorities have recommended people who work in high-density areas wear a surgical or disposable mask; in Hong Kong authorities have recommended wearing a disposable mask when taking public transportation.
 
The authors write that while there's still scarce evidence to show that masks prevent respiratory infections from spreading, vulnerable individuals may want to consider wearing a surgical mask when in high-risk areas, where there are crowds of potentially infected people. It may also be rational to recommend that anyone in quarantine who needs to go outside wears a mask "to prevent potential asymptomatic or presymptomatic transmission," they write. Additionally, they say that as evidence shows COVID-19 may be transmitted before people show symptoms, community transmission might be reduced if everyone—especially infected but still asymptomatic people—could wear a mask.
 
Still, they say that for now, available masks should be given to healthcare workers and other vulnerable individuals first. More widespread mask wearing should be considered only once supplies permit.
 
Best Steps for Prevention
Though masks are considered appropriate for only a small percentage of people, everyone should take the following steps to help prevent the spread of coronavirus and other infections.
 
First: Practice social distancing. Stay home as much as possible, and when you do have to go out, avoid crowds and keep 6 feet between you and others.
 
“Impeccable hand hygiene is [also] key,” says Isaac Bogoch, M.D., an epidemiologist and associate professor of infectious disease in the department of medicine at the University of Toronto. That’s to protect you from exposure to droplets of fluid from coughs or sneezes that contain the virus.
 
Wash hands frequently, scrubbing thoroughly for the recommended 20 seconds.
 
Use hand sanitizer when you can’t get to a sink—after touching a handrail or door handle, on public transit, or using a shared keyboard at the library, for example.
 
Abstaining from touching your face is also important, because that’s how germs get transferred from your hands to your mouth or nose, and enter your body. “It’s easy to say but hard to do,” Bogoch says, but now is the time to make this a habit.
 
And of course, cover any coughs or sneezes with a tissue, and if you can’t, sneeze or cough into the crook of your elbow.