Proper mask etiquette is a confusing part of the coronavirus epidemic, but it’s also become more than just a suggestion. Many places are requiring they be worn in public, and some businesses are mandating their use as well. So know this: The CDC recommends wearing some type of face covering while in public, especially when it’s tough to maintain 6 feet of social distancing, such as at grocery stores and pharmacies.
Yes, the science on face masks is mixed, especially because little data is available for COVID-19.
The CDC says face coverings aren’t a substitute for social distancing. When in public, people should still stay at least 6 feet apart to prevent the spread of the virus.
Here’s a more comprehensive guide to masks, with links to articles and research, to answer some of the most common questions:
The CDC says that wearing a mask won’t necessarily prevent you from getting sick, especially if you move the face covering or it doesn’t fit snugly against your face. But masks will reduce the distance that your respiratory droplets travel while coughing, sneezing, or talking. This prevents others from getting sick and reduces the spread if you’re infected but don’t have symptoms.
Several studies have shown that wearing a face mask can slow the spread of respiratory droplets, which is how SARS-CoV-2, the virus that causes COVID-19, is transmitted. The virus can be spread by droplets as small as 5 microns or micrometers, a group of scientists for the National Academies of Sciences, Engineering and Medicine wrote to the White House in an April 8 letter.
After the 2003 epidemic of SARS, which is a coronavirus similar to the one causing the current pandemic, a study in Hong Kong found that no health care workers who wore a surgical mask or respirator got infected, and only about 7% of those who wore a handmade mask got infected.
A 2013 study by researchers in the U.K. found that 100% cotton shirts used as homemade face masks could have 69% effectiveness for organisms that are about the same size as flu viruses, and linen had about 60% effectiveness. But with COVID-19, scientists can’t say for sure.
“Our findings suggest that a homemade mask should only be considered a last resort to prevent droplet transmission from infected individuals, but it would be better than no protection,” the U.K. researchers wrote.
A small study in South Korea found neither surgical nor cotton masks effectively filtered the virus when an infected patient coughs. While the study has gained attention, it was only conducted on four patients, which is too small a study to apply to the world at large.
Still, the study found while the masks helped some, surgical masks prevented just 5% more virus droplets than no mask at all. Cotton masks fared better, with a 27% increase in blockage. Researchers also found higher amounts of the virus on the outside of masks than on the inside.
For now, health officials are encouraging people to wear masks and face coverings in public to stop the spread of COVID-19.
“Mass masking for source control is in our view a useful and low-cost adjunct to social distancing and hand hygiene during the COVID-19 pandemic,” public health researchers from the United Kingdom and China wrote in an April 16 article in journal The Lancet.
“As with parachutes for jumping out of aeroplanes, it is time to act without waiting for randomized controlled trial evidence,” researchers from several countries wrote in a BMJ article on April 9. The article outlines several systematic reviews they found of masks and respirators.
The CDC recommends using cloth face coverings and has asked the public to reserve surgical masks and N95 respirators for health care workers who need supplies to treat COVID-19 patients.
Cloth face coverings can be made from household items such as fabric, shirts, pillowcases, or sheets.
With children, finding the right fit is important, according to the American Academy of Pediatrics. Pleated masks with elastic can be adjusted easily, but adult sizes and some kid sizes may still be too large. Find a size that fits the face and adjust it. The CDC says a mask should be snug against the side of the face, but not so tight as to be uncomfortable.
Putting a filter between the layers of fabric may help, and if you choose to do this, make sure the mask has a pocket for the filter so you can remove it to wash the mask. Experts say a cut piece of a HEPA filter, like those found in air conditioners or furnaces, work well. Some have even suggested cut pieces of vacuum cleaner bags.
Believe it or not, there is a protocol to putting on and taking off masks. Wash your hands before you put the mask on your face, and grasp it by the edges. Loop the ties or fasteners behind your ears, and try not to touch the cloth that covers your mouth and nose, which can contaminate the surface.
While wearing the mask at the grocery store or another public setting, don’t touch the mask or pull it down. If the mask covers your mouth but not your nose, for instance, it’s still possible to spread the virus. Remember that the mask may have contaminants, so leave it on if you’re driving home from the store and take it off at home.
When removing the face covering, don’t touch your eyes, nose, or mouth. Wash your hands immediately after removing, the CDC says. Place the mask in a plastic bag until you’re ready to wash it. Masks should be considered “dirty” and contaminated after each use. Wash it in a washing machine with soap and hot water, and dry it in a dryer.
If you make a homemade mask, cotton fabric works well. Use rubber bands, cloth strips, hair ties, or repurposed straps for the ear loops. Tightly woven cotton, such as quilting fabric or cotton sheets, are a good option, according to the CDC, and T-shirt fabric and bandanas can work also. Thicker fabric with multiple layers is best.
Since face coverings should be washed after each use, synthetic fabrics that can’t be washed or dried on high heat may not be the best idea.
The CDC features three ways to make face coverings on its website, including a sewn cloth face covering from cotton fabric, a simple no-sew method by cutting and tying a T-shirt, and another no-sew option by folding and tucking a bandana. The page features two videos as well.
Children under age 2 should not wear masks, according to the American Academy of Pediatrics (AAP). Children and teens above age 2 should wear masks in public, following the same recommendations as adults.
If children are at home with usual family members or residents, they don’t need to wear a mask if they haven’t been exposed to anyone with COVID-19, the group says.
In most cases, children don’t need to be in public under stay-at-home guidelines, especially if one family member runs errands or leaves the home for groceries, medications, or other essential purposes. If children can’t be left at home, or if they go into public in emergency situations such as a doctor’s appointment, masks are recommended.
In addition, children don’t need to wear masks while outside as long as they don’t touch surfaces that could have the virus, such as tables, water fountains, and playground equipment. But younger children may require more precaution.
“Especially for younger children who may not understand why they can’t run up toward other people or touch things they shouldn’t, the best approach is to keep them home and in spaces away from other people and common surfaces,” the AAP says.
When possible, speak with children about the virus and explain why a mask is a safety measure for both themselves and others.
“My children are aware of what’s going on and they understand viruses and how they spread,” said Casey Noel Green, a photographer in Newnan, GA, with a 7-year-old son and a 9-year-old daughter. “We answer their questions honestly when they ask and explain why things like hand hygiene and social distancing are important.”
The American Academy of Pediatrics suggests a few other things as well:
CDC: "Use of Cloth Face Coverings to Help Slow the Spread of COVID-19," "Cloth Face Coverings: Questions and Answers."
American Academy of Pediatrics: "Masks and Children During COVID-19."
Disaster Medicine and Public Health Preparedness: “Testing the Efficacy of Homemade Masks; Would They Protect in an Influenza Pandemic?”
Lancet: “Effectiveness of precautions against droplets and contact in prevention of nosocomial transmission of severe acute respiratory syndrome (SARS),” “Wearing face masks in the community during the COVID-19 pandemic: altruism and solidary.”
Journal of the American Medical Association: “Masks and coronavirus disease 2019 (COVID-19)."
National Academies of Sciences, Engineering and Medicine: “Rapid Expert Consultation on the Effectiveness of Fabric Masks for the COVID-19 Pandemic.”
BMJ: “Face masks for the public during the covid-19 crisis.”
Caylin Riley, MD, Dayton, OH
Casey Noel Green, Newnan, GA.
Today: “Do you need a filter for your homemade face mask?”
Annals of Internal Medicine, “Effectiveness of Surgical and Cotton Masks in Blocking SARS–CoV-2: A Controlled Comparison in 4 Patients FREE.”