The CDC is still advising against the general public wearing traditional medical masks, such as surgical variants and N95 respirators, to preserve them for health care workers. The shift in messaging on cloth masks, the agency said, came in light of evidence that people with few or no symptoms of Covid-19 can still transmit the virus.
The upshot: Masks can help stop the spread of coronavirus not just by protecting the wearer, but by preventing the wearer — who could be an asymptomatic spreader — from breathing and spitting their germs everywhere. Some studies in households and colleges “show a benefit of masks,” Raina MacIntyre, head of the Biosecurity Research Program at the University of New South Wales in Sydney, Australia, told me, “so it would be plausible that they would also protect in lower-intensity transmission settings such as in the general community.”
But masks do not make you invincible. They can’t replace good hygiene — Wash your hands! Don’t touch your face! — and social distancing, both of which have been key to stemming the coronavirus even in Asian countries where widespread mask use was already common. Epidemiological models also suggest coronavirus cases will rise if social distancing measures are relaxed, potentially causing hundreds of thousands, if not millions, of deaths in the US alone. That’s true whether people are gathering wearing masks or not.
Still, the CDC’s about-face has left many people with plenty of questions: What does it mean to use a mask correctly? When should they be used and washed? Do you need them for all public situations? Can they really keep you safe? If you can’t find a mask, how can you make one?
And why aren’t there more medical masks to begin with?
Here’s a guide to some of the most common questions.
1) When should I wear a mask?
According to the CDC, you should wear a mask in public, particularly while in “settings where other social distancing measures are difficult to maintain (e.g., grocery stores and pharmacies)” and “especially in areas of significant community-based transmission.”
Think of circumstances where it’s going to be harder to keep at least 6 feet away from other people, especially in closed, poorly ventilated places. It’s in those kinds of situations that coronavirus-containing droplets are more likely to spread by air or surfaces.
There are some exceptions to the mask guidance, the CDC stated: “Cloth face coverings should not be placed on young children under age 2, anyone who has trouble breathing, or is unconscious, incapacitated or otherwise unable to remove the mask without assistance.”
And be warned: If you use a mask incorrectly, or start acting recklessly because you’re wearing a mask, it could actually hurt you more than it helps.
If you fidget with your mask, and especially if you touch your face in the process, you can infect yourself with virus-containing droplets your mask caught. If you reuse a mask without cleaning it, you can breathe in or otherwise expose yourself to droplets the mask captured last time. If you generally ease up on good hygiene or social distancing because you’re wearing a mask, you’re putting yourself — and your community — at greater risk.
The CDC offers some tips for how to properly use a mask. Above all, don’t touch the mask and then touch other parts of your face, especially your eyes, mouth, and nose. The entire point of this fabric is to shield you from outside germs. So you don’t want to touch the part of the mask doing the shielding and then the parts of your face that are vulnerable to infection.
You should also wash your hands before and after taking off a mask — before to avoid getting anything on your face and mask, and after to get rid of anything that was on your mask. Remove the mask with the loops, not by touching the front. If possible, throw away disposable masks after using them. And if you can’t throw a mask away, make sure to thoroughly disinfect it with ultraviolet light sterilizers — not something most people have around — or, if using a cloth product, throw it in the wash or clean it with soap and water.
For some people, it might make sense to have multiple masks around if you have to go out multiple times on a particular day. The important thing, though, is to throw a recently used mask in the laundry or in the wash as soon as possible and avoid touching it at all until it’s clean. Do not keep dirty masks around your house, where people can easily touch them and potentially infect themselves.
2) What kind of mask should I use?
The CDC recommends a cloth mask or face covering, whether a professionally made mask or a homemade variant.
The CDC explicitly advises against the general public using a surgical mask, which is the standard mask you’ve probably seen doctors and nurses wear. It also advises against the public using N95 respirators, which are more complex, expensive masks meant to fit more tightly on the face.
Surgical masks and N95 respirators, the agency noted, “are critical supplies that must continue to be reserved for healthcare workers and other medical first responders, as recommended by current CDC guidance.”
As it stands, there is a serious shortage of PPE, including masks, for health care workers. There are reports of doctors, nurses, and other health care workers using bandanas and scarves for masks and trash bags for gowns. Hospitals are considering do-not-resuscitate orders for dying Covid-19 patients out of fear that such intensive, close-up procedures could get doctors and nurses without PPE infected with the virus. The CDC, acknowledging the shortage, previously recommended homemade masks for health care workers when no other options are available.
“I am worried that telling people to wear masks will strain already weak supplies that are needed by doctors and nurses,” Jennifer Nuzzo, an epidemiologist at Johns Hopkins University, told me. “If we are able to fix that supply chain, I’d feel less worried about this. But some of the shortages initially were due to members of public and medical staff raiding medical offices’ and hospitals’ supplies for home use.”