One mask provides good protection against spreading the coronavirus, but two masks could offer more.
As more-contagious variations of the virus are discovered, the notion of doubling up on masks is gaining traction, especially for those likely to become severely ill if they get infected.
Though the Centers for Disease Control and Prevention does not have guidelines on double-masking, Dr. Anthony Fauci, the nation’s top infectious disease expert, says it “just makes common sense” that two masks may be more likely to protect against COVID-19.
Leading health experts say fit and materials determine masks’ efficacy against coronavirus transmission. Poorly fitted masks can allow air leaks around the nose and mouth. Materials that are too thin are less effective at blocking particles in the air.
Many Americans have yet to double-mask. In a recent poll a majority (61%) have never worn two face masks on top of each other.
Using two masks has a double benefit: an extra layer of material and a better-fitting face covering. A July study in the peer-reviewed journal “Matter” found that a single mask is 50% effective at filtering out aerosols. A second face covering is up to 90% effective.
It not only adds an extra layer of protection but also makes the mask fit more snug, said Dr. Loretta Fernandez, an associate professor at Northeastern University and one of the study’s authors.
“We found that the particle removal efficiency of many surgical style masks could be improved by up to 50% by simply snugging the mask material to the face,” she said.
“In the lab, we did this by adding a nylon stocking, but also tested other elastic layers such as gators and tights and found that they also solved the problem of cutting off air leaking in from around the mask.”
Choosing better materials
Not all face coverings can protect you effectively from infectious respiratory particles.
Masks made of thin materials, such as a bandanas and neck gaiters, have a loose weave, which allow for large droplets to escape and do not provide a reliable level of protection from inhaling smaller airborne particles, according to clinical trials. Thin materials are worse because some of the most comfortable masks are usually thin and don’t do a good job of blocking particles.
Snug fitting masks provide better protection
When double-masking, a tighter-fitting mask with ear loops or elastic band straps should be worn closest to the face. It will help filter the virus’ small aerosol droplets. Surgical masks protect the wearer’s nose and mouth from contact with droplets, splashes and sprays that may contain germs.
The pros and cons
Layering is key
How to wear double-mask comfortably
A surgical mask should sit over your nose, mouth and under the chin with no gaps on either side. Layering with the second mask of cotton fabric will keep the first mask snug in place and provide added protection.
Masks shouldn’t be so tight that they restrict your ability to breathe. If you feel light-headed, take off the first mask.
If the double mask seems too much, a cotton mask with a filter pocket may be better. Adding any sort of filtering inside the mask may help to reinforce it and add additional protection. An engineer specializing in aerodynamics has tested the effectiveness of paper towels. A single layer captured 23% of particles 0.3 microns or larger. Adding an extra layer increased particle capture to 33%.
N95 respirators are tight-fitting and have interlacing fibers to block out at least 95% of airborne particles as small as 0.3 microns. They have a protection factor (APF) of 10, according to the CDC. That means the N95 reduces the aerosol concentration to 1/10 of that in the room — or blocking 90% of airborne particles.
When to wear double-masks
If you know you will be in close contact with several people outside of your household, such as a grocery store, double-masking is recommended. While outside on a walk and not in close range of others, a single mask should be sufficient.
Given that highly contagious COVID-19 variants are spreading across in the U.S., doubling up on masks may be more important than ever. Continued masks wearing, social distancing and good hand hygiene are essential in the fight against the coronavirus.
SOURCE Centers for Disease Control and Prevention; Healthaffairs.org and USA TODAY research; CONTRIBUTING Adrianna Rodriguez and Karina Zaiets, USA TODAY