WHO: Fabric Face Masks Should Have 3 Layers

This spring, the World Health Organization (WHO) recommended that healthcare workers, people who are infected with COVID-19, and those who are caring for people with COVID-19 wear medical face masks to protect against the virus. On June 5, WHO shared updated guidance on wearing masks, recommending them for a wider group of people and sharing specifics on the best kind of non-medical fabric masks.

WHO now recommends that you wear a three-layer fabric face mask every time you go in public where social distancing is impossible. And, if you are 60 or older or have an underlying health condition, you should wear a medical mask in situations where physical distancing isn’t possible.

WHO emphasizes that masks can help prevent the spread of COVID-19. “Current evidence suggests that most transmission of COVID-19 is occurring from symptomatic people to others in close contact, when not wearing appropriate [personal protective equipment],” the guidance says.

What Should Fabric Masks Be Made Of?

The guidance goes into specifics about what, exactly, these three-layered fabric masks should be made of:

• An inner layer of absorbent material, like cotton
• A middle layer to act like a filter or barrier, made of non-woven material like polypropylene
• An outer layer of a non-absorbent material, like polyester or a polyester blend

WHO recommends avoiding materials that are stretchy—they have poor filtration ability and are sensitive to washing at high temperatures—as well as those that are made of silk or gauze.

How to Upgrade Your Current Mask

You probably already have a mask, or several masks, that may not meet the new WHO criteria. Can you make adjustments to your current mask without getting a new one?

It’s possible, Suzanne Willard, PhD, a clinical professor and associate dean for global health at the Rutgers School of Nursing, told Verywell. However, she stresses that it’s important to make sure you can still breathe. “I worry that there will be limited airflow and people will get hot and not wear them,” she said.

Here are a few things you can do to enhance a basic cloth facial covering to meet WHO standards:

• Wear two. “If you have more than one mask at home, you can layer them,” David Cennimo, MD, director of East Orange VA Medical Center and assistant professor of medicine-infectious disease at Rutgers New Jersey Medical School, told Verywell. However, he seconds Willard's concerns about being unable to breathe well.
• Add a filter to your mask. You can split a seam in your existing mask and insert a filter, like a coffee filter, Willard said. You can remove this filter when you wash your mask and either throw it out or reuse it later.
• Be creative. “Whatever you can come up with is probably good,” Andres Romero, MD, an infectious disease specialist at Providence Saint John’s Health Center in Santa Monica, CA, told Verywell. “You want a close-fitting mask that ideally has three layers, but anything is better than nothing, particularly in those settings where you can’t keep social distancing.”

Will More Layers Make a Difference?

Even the best fabric face masks aren’t as efficient as medical-grade masks, like N95 respirators. Medical masks can filter out up to 95% of aerosolized particles, while cloth face masks have only been shown to filter out anywhere from 0.7% to 60% of particles. However, the Centers for Disease Control and Prevention (CDC) says medial masks should be reserved for healthcare works and first responders.

Still, wearing a fabric mask with several layers could help in preventing a second wave of COVID-19 infections. WHO lists non-medical masks as a potential benefit for source control.

“A mask will hopefully catch the droplet particles you produce,” Cennimo said. “Multiple layers in a mask are more likely to do that.”

A Word From Verywell's Medical Expert Board

"Masking is one of the easiest and most effective ways to prevent coronavirus spread. It’s particularly important since we don’t yet have a vaccine or treatment. But you don’t need to find a medical mask to protect yourself. You can buy or make a cloth face covering with three layers. The middle layer should be a filter—even a paper coffee filter will work. And remember, masking is in addition to—rather than instead of—social distancing!" — Anju Goel, MD, MPH

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.