The Centers for Disease Control and Prevention has released new research suggesting that wearing two masks may be more effective at preventing the spread of COVID-19.

The study showed that wearing a cloth mask over a surgical mask helped improve the fit of the surgical mask and can reduce the spread of respiratory droplets by up to 92%, if both individuals are wearing two masks. 

“The fact that they got 92% means that there’s this effect of greatly improved fit preventing leakage out of the sides,” said Dr. Lindsey Marr, professor of civil and environmental engineering. “It’s the combination of the filtration and the fit.”

An effective cloth mask is usually multilayer and made of water-resistant fabric with a fine weave. A surgical mask is a disposable mask that is loose-fitting and serves as a barrier between the face and contaminants. A cloth mask alone blocks 51.4% of particles and a surgical mask alone blocks 56.1% of particles.

Wearing a mask has already been shown to decrease the wearer’s exposure to respiratory droplets, but cloth masks and surgical masks do not fit as well as respirators such as N95 respirators. A N95 respirator is a respiratory device that forms a seal around the nose and mouth and is a very effective filter. Improving the fit of a mask can help with filtration to prevent air from flowing in through the sides of the mask. 

Some ways to improve the fit of a mask include using nose wires at the top of the mask to prevent leakage, mask fitters or bracers that are worn over a surgical mask to help the mask fit more snugly and knotting the ear loops of the mask and folding and tucking the corner material under the edges.

“Fitters have been scientifically demonstrated to improve filtration performance by as much as 90% or more, which, again, is getting into that range of filtration efficiency afforded by N95 respirators,” said Dr. John Brooks, the chief medical officer for the CDC’s COVID-19 response.

Since COVID-19 mostly spreads through respiratory droplets from breathing, coughing or talking, wearing a mask over the nose and mouth can prevent respiratory droplets in the air from landing in the wearer’s respiratory tracts.

Another way to increase the mask wearer’s protection is to improve the filtration of the mask. This can help contain the wearer’s respiratory droplets from spreading into the air as well as protect the wearer from respiratory droplets in the air that might contain the virus.

Wearing a cloth mask over a surgical mask provides more protection than a cloth mask or a surgical mask alone. Improving and encouraging proper mask usage can reduce the spread of COVID-19 and slow the emergence of new strains that may be more contagious or cause more severe disease. 

“We know that universal masking works,” Brooks said. “And now these variants are circulating; whatever we can do to improve the fit of a mask to make it work better, the faster we can end this pandemic.”

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