Skip to main content

Should you wear a face mask to prevent COVID-19? Experts disagree.

It may be a good idea to wear a face mask in a crowded place, such as an airplane, during the COVID-19 outbreak.
It may be a good idea to wear a face mask in a crowded place, such as an airplane, during the COVID-19 outbreak.
(Image: © Shutterstock)

Editor's Note: On April 3, the Centers for Disease Control and Prevention began recommending that people wear face coverings in public. You can read that coverage here. The below article was written before this recommendation was issued.

The public doesn't need to wear heavy-duty respirators, but it's a smart idea to don a face mask or wrap a clean scarf around your nose and mouth if you're going into a crowded place during the COVID-19 outbreak, an infectious disease doctor told Live Science.

The Centers for Disease Control and Prevention (CDC) may soon agree with this assessment; the agency currently states that healthy people do not need to wear face masks unless they are caring for someone who is ill with the new coronavirus. But an anonymous federal official said that the CDC may change these guidelines, in effect encouraging people to cover their faces in public, The Washington Post reported on March 30.

That said, the public does not need to wear face masks most of the time, said Dr. Otto Yang, a professor in the Department of Medicine and the Department of Microbiology, Immunology and Molecular Genetics at the David Geffen School of Medicine at the University of California, Los Angeles.

Related: How does the new coronavirus compare with the flu?

If you're out for a walk — in essence, going to a setting where you can be at least 6 feet (1.8 meters) from other people, "then I think that not having a mask is fine and that fits the CDC recommendations," Yang said.

But, in his opinion, "If you have to be in a crowded situation, perhaps on a plane or waiting in line at the airport, it might make sense to wear a mask," Yang told Live Science. 

The discussion about face masks has become a national conversation. Many people in the public are buying face masks to protect themselves. But health care experts have urged against hoarding, since these supplies are desperately needed in hospitals. Even the U.S. surgeon general tweeted "Seriously people — STOP BUYING MASKS!"

"The CDC, it's like they're talking out of both sides of their mouth," Yang said. "One side of their mouth is telling the general public, 'Hey, you don't need masks, forget about it.' The other side is, 'Health care workers need to wear N95 respirators.'"

"Is that a double standard?" Yang said. "Are they valuing some people more than others?"

Droplets or aerosol

Some of the confusion about "masks versus N95 respirators" exists because so little is known about COVID-19. At first, it wasn't clear if the virus spread predominantly through large respiratory droplets (like influenza) or also through a fine mist, called an aerosol, which can linger for hours (like measles). This great unknown made it unclear whether a heavy-duty mask, known as an N95 respirator, which blocks the smallest virus particles, or a regular surgical mask, which only blocks larger droplets, was better suited to protect against the virus.

At first, the CDC advised health care workers to wear N95 respirators because it wasn't clear whether COVID-19 could spread through aerosol. A March 17 study in the New England Journal of Medicine (NEJM) seemed to justify the fear of airborne spread, showing that the new coronavirus SARS-CoV-2 could survive in the air for up to 3 hours as an aerosol. 

But Yang doesn't see it that way. The new study showed that the virus was viable as an aerosol in a lab, but not in real life, he said. In the study, the researchers "took extremely concentrated virus, much more concentrated than a person makes, they used an artificial aerosol machine [a nebulizer], which probably generates way more aerosol than a normal person does," Yang said. "So their conclusions were in this system."

Related: Are viruses alive?

The researchers of that study looked at SARS-CoV-1 (the original SARS from the 2003 outbreak) and SARS-CoV-2 and found that both could be aerosols. "But we already know that the original SARS virus was not transmitted that way," in the general public, so that makes their model "not very believable," Yang said.  

In other words, except in certain hospital situations such as a bronchoscopy, which essentially creates a fine mist of virus, SARS-CoV-2 is likely spread mostly through droplets, like the flu, Yang said. That's supported by a Feb. 24 case report in the Canadian Medical Association Journal, which found a man sick with COVID-19 on a flight from China to Canada in January did not infect his fellow passengers, even though he had a dry cough during the 15-hour flight. The man was wearing a face mask, but because no one else on the plane got infected, this case "supports droplet transmission, not airborne, as the likely route of spread of the COVID-19," the researchers of the case study found.

However, it's still unclear whether the virus can spread through aerosol. For example, after the Skagit Valley Chorale in Washington met for rehearsal on March 6, 45 of its members were diagnosed or showed symptoms of COVID-19, at least three were hospitalized and two were dead within three weeks, according to the Los Angeles Times. Perhaps the choir singers' forceful breathing as they sang dispersed the viral particles, Jamie Lloyd-Smith, an infectious disease researcher at the University of California, Los Angeles and a co-researcher on the NEJM study, told the Los Angeles Times. 

"One could imagine that really trying to project your voice would also project more droplets and aerosols, Lloyd-Smith said.

N95 respirator or face mask?

Due to the N95 respirator shortage, the CDC recently relaxed its guidelines, saying that among health care workers, face masks were "an acceptable alternative when the supply chain of respirators cannot meet the demand," except in situations when respiratory aerosols might be produced, such as intubation or nebulizer treatments. 

In addition to the shortage, N95 respirators are challenging to put on. Doctors receive annual training on how to mold the respirator around the face. As a test, doctors put on a hood and have the artificial sweetener saccharin sprayed in. "If you're wearing the mask properly, you don't taste any saccharin," Yang said. But most people do, he noted. 

For this reason, the N95 respirator isn't recommended for the public, since it requires training to put on properly. Moreover, the N95 respirator is thick, so it's hard to breathe through.

In a nutshell, the public does not need N95 respirators; they likely will not be in a situation where they're exposed to aerosol of the virus, and these masks are needed by health care workers who will, Yang said.

"There's no reason for the general public to wear N95's," Yang said.

However, even regular face masks are in short supply, prompting the CDC to recommend the use of bandannas and scarves when necessary. There's not a lot of research on homemade masks, but a small 2013 study found that masks made from cotton T-shirts were effective, though not as good as surgical masks.

"The surgical mask was three times more effective in blocking transmission [of microorganisms] than the homemade mask," the researchers of that study found, who noted that homemade masks "should only be considered as a last resort to prevent droplet transmission from infected individuals."

Related: Tiny & nasty: Images of things that make us sick

For people opting to use scarves and homemade masks, Yang recommended washing them after every use, and to stop wearing them when damp from breathing. Wearing eye protection, such as a face shield or goggles, could also physically block the virus, said Yang and Dr. James Cherry, a professor of pediatric infectious diseases at the David Geffen School of Medicine, University of California at Los Angeles.

In a 1987 study Cherry did with colleagues, health care workers who wore face masks or goggles were less likely to get respiratory syncytial virus (RSV) from hospitalized children than doctors who did not take these measures.

However, unlike Yang, Cherry agreed with the current CDC guidelines, and said that except for certain exceptions, the public doesn't need to wear face masks, as did Dr. Jaimie Meyer, an infectious disease specialist at Yale Medicine. That's especially true given that the safest way to avoid being exposed, or exposing others, is to simply stay home.

"The current CDC guidance says the general public does not need to be wearing surgical masks," Meyer told Live Science. "The best protection is to focus on social distancing, hand-washing, not touching their faces and bleaching high touch surfaces."

Originally published on Live Science.

OFFER: Save at least 53% with our latest magazine deal!

With impressive cutaway illustrations that show how things function, and mindblowing photography of the world’s most inspiring spectacles, How It Works represents the pinnacle of engaging, factual fun for a mainstream audience keen to keep up with the latest tech and the most impressive phenomena on the planet and beyond. Written and presented in a style that makes even the most complex subjects interesting and easy to understand, How It Works is enjoyed by readers of all ages.View Deal

  • LytchZam
    Photo shown on TV of a line at the airport - all were pilots and crew - maybe 20 of 'em - and they all - all - had on masks, and most were wearing gloves.

    IF you can have no symptoms, but still may be contageous, wouldn't it make sense for everyone to wear a mask so those cases can be covered. You don't think you need a mask, because you have no symptoms, but you do because you're contageous: so you'd be doing everyone a favor by wearing a mask to begin with.
    Reply
  • LindaG
    Conflicting recommendations from physicians and scientists don't help. To me it is just logical that even a mask that is not fitted perfectly is going to help. No, it is not guaranteed; but there are asymptomatic individuals that are likely to be at the grocery store with me. Why would I not protect myself if I can? BTW, I do have N95 masks which I purchased 2-3 YEARS ago for a different reason. So I am not hoarding or buying masks now that would otherwise be available to health care professionals who need them. I would not do that.
    Reply
  • RMLNZ
    Wearing even a simple mask will reduce your ability to infect other people by droplets or aerosols.

    So, it makes sense to wear one for the good of others just when you are around them.

    If you're not feeling well then its imperative to wear one when other people are around.

    Obviously, simple masks will be less effective in stopping you catching Covid-19. For that you need high quality medical masks.

    At the end of the day wearing masks is uncomfortable and hot and it messes with your nose and throat.
    Reply
  • Baborrymask
    In China, general population uses Surgical Mask, health care workers at least use an N95 mask and wear a medical protective suit plus protective goggle. Currently, antivirus masks and other protective equipment are sufficient, and many masks and protective equipment mainly been exported to other countries who need them.
    Reply
  • honestj
    There is a reason all these guys give you crap advise. Because you want guarantees for everything , otherwise some pathetic lawyer will team up with you to sue whoever gives you honest advise. This is the reason that little tiny lingerie comes with at least 5 huge tags stitched to it , one from state of california, some from 4 other crap agencies, all to 'protect you'. No one wants to speak the truth, beccause everyone fears the invisible craplawyer present in the room. The truth is that if everyone wears an appropriate mask, it would indeed 'harden' the environment against the virus, make life less fun for the virus. And you dont need to be Einstein to figure it out. Just use common sense. Oh i am sure hte FDA will say 'there is no evidence in any of the published double blind studies that shows that common sense is of use'. You bet! So now you have the CDC that says 'wear kerchiefs or anything you can get' and the FDA which is blocking imports of life saving masks from China and the surgeon general says 'people, stop buying masks' (wow, what a professional sounding statement) .. i am sure his esteemed highness has nothing against you buying caskets.. So shut up , use common sense and protect yourself, and stop deluding yourself that the government exists to 'take care' of you..
    Reply
  • Brian
    RMLNZ said:
    Wearing even a simple mask will reduce your ability to infect other people by droplets or aerosols.

    So, it makes sense to wear one for the good of others just when you are around them.

    If you're not feeling well then its imperative to wear one when other people are around.

    Obviously, simple masks will be less effective in stopping you catching Covid-19. For that you need high quality medical masks.

    At the end of the day wearing masks is uncomfortable and hot and it messes with your nose and throat.
    Wearing mask for mutual protection probably only makes sense when you are in situations where maintenance of social distancing is not possible like on public transportation, and situations where you are required to work closely with others.
    For protection of others it should probably be mandatory for kitchen workers, servers, and those who handle bulk produce in grocery stores
    Reply
  • Tommy Shenanigans
    Unfortunately the most fake news has been supplied by our "experts". ie. "The virus is only .8 contagious as the flu (early March) . Now it's 3 times. It is contracted from airborne and surface contamination. But "we do NOT recommend wearing a mask". Oh, and the only reason they "recommended" that deadly advice (not to protect yourself) was to ensure there wasn't a run on masks! Yeah, good! Instead of preventing the disease from spreading (and healthcare workers not needing tons of masks) they encouraged it! And guess what? Now healthcare workers are in an even bigger shortage and it's not only masks it's ventillators and other equipment! It has also been made clear that you can get it in your eyes from touching or airborn transimission ...yet seems nobody but me has figured you need goggles as well. Social distancing is the cure?! What about the A/C ventilation?! Remember Legionaire's disease? I've been wearing an N99 RV mask, swim goggles, and gloves on every shopping trip since early March .... at least one of the people who were shaking their head at me back then is now dead. American sheep. If you think it's not cool to wear a mask you're both wrong and an idiot.... the prime target of the virus.
    Reply
  • Brian
    Tommy Shenanigans said:
    Unfortunately the most fake news has been supplied by our "experts". ie. "The virus is only .8 contagious as the flu (early March) . Now it's 3 times. It is contracted from airborne and surface contamination. But "we do NOT recommend wearing a mask". Oh, and the only reason they "recommended" that deadly advice (not to protect yourself) was to ensure there wasn't a run on masks! Yeah, good! Instead of preventing the disease from spreading (and healthcare workers not needing tons of masks) they encouraged it! And guess what? Now healthcare workers are in an even bigger shortage and it's not only masks it's ventillators and other equipment! It has also been made clear that you can get it in your eyes from touching or airborn transimission ...yet seems nobody but me has figured you need goggles as well. Social distancing is the cure?! What about the A/C ventilation?! Remember Legionaire's disease? I've been wearing an N99 RV mask, swim goggles, and gloves on every shopping trip since early March .... at least one of the people who were shaking their head at me back then is now dead. American sheep. If you think it's not cool to wear a mask you're both wrong and an idiot.... the prime target of the virus.
    There is growing evidence that this virus exists not only in our snot and spit, but can be found in our poop as well, even days after it is no longer evident in our saliva and mucus. This to me means it is not only respiratory but gastrointestinal as well, and probaby means it can be acquired by eating virus contaminated produce, or cooked food that has been recontaminated after cooking during the serving or eating activities. Wondering if you are doing anything special to keep what you eat and drink virus free?
    Reply
  • Eddie Would Go
    There are no "experts" who say masks don't work, only idiots and liars. There is ample scientific evidence that masks are effective if you use them every time you are near an infected person, and it is simple physics and observation that a mask will both prevent spit from being projected from your mouth and keep spit from another person entering your mouth.

    These idiots who think that something has to be 100% effective before you can recommend them are just plain stupid. There is no danger from over killing protective measures. There is absolute danger from not doing enough. Stop being stupid.
    Reply