Doubling up on masks has become a common practice for those seeking an extra layer of protection against the coronavirus, especially with new, more infectious variants on the loose. Do studies actually show two masks are more effective than one in fending off COVID-19? The advice from the medical community is varied, but the bottom line is quality over quantity.
In the U.S., White House adviser Dr. Anthony Fauci told NBC News on Monday that when it comes to adding another layer of protection, “it just makes common sense that it likely would be more effective.”
As Dr. Monica Gandhi and virus expert Linsey Marr explain in their study published Jan. 15 in the Med journal: “Masks work by blocking or filtering out viruses that are carried in aerosols ... air must curve as it flows around individual, tightly packed fibers of the material, like a race car swerving around cones of an obstacle course. As the air curves, the aerosols it carries cannot make the sharp bends and therefore slam into the fibers, or they come too close to the fibers and stick to them.”
With that in mind, it would seem to make sense that more layers would make it harder for the virus particles to successfully navigate their way to your mouth or nose.
Indeed, scientists concur that doubling up is important for those who prefer to wear cloth masks. Research by the U.S. Centers for Disease Control and Prevention (CDC) has shown multilayer cloth masks only block 50%-70% of fine droplets and particles. Therefore, wearing a disposable nonwoven mask underneath your favorite cloth masks is a suitable way to get the protection that might be afforded by a higher quality mask, Gandhi and Marr said.
The best means of protection, however, is simply to wear a snuggly-fitting, high-quality mask, while also abiding by social distancing.
Dr. Alpay Azap, a faculty member in Ankara University’s Department of Infectious Diseases and Clinical Microbiology and a member of Turkey’s Coronavirus Scientific Advisory Board, told the Cumhuriyet newspaper in December that “a good quality mask is enough.”
As long as your mask has three layers, with a middle layer that isn’t permeable, “it cannot be said that the double mask is more protective than a single mask,” he said. Surgical masks have been shown to filter out 70%-80% of fine particles, while N95 masks filter out 95%, as their name suggests.
“In addition, when two masks are worn, the need for continuous correction may occur due to the sliding of the masks. This can cause us to spread the infection by touching our eyes, mouth and nose, as it will prompt us to bring our hands to our face more often,” Azap explained.
Furthermore, double mask-wearing should be avoided for those with chronic heart or lung diseases such as asthma or chronic obstructive pulmonary disease (COPD), Dr. Hakan Oğuztürk, an emergency training officer at Ankara City Hospital, told the Hürriyet daily. Wearing two masks could pose problems for people who already struggle to get enough oxygen, he explained.
Oğuztürk said mask-wearers can verify the quality of their surgical masks by checking that they are approved by the Health Ministry using the online barcode tracking system.
If your mask has been approved for medical use, “I can say with peace of mind that it is ideal to use it as a single mask,” he said.
