Before you double mask, make sure the first one fits
Tighten up, double up.
That’s the latest word from the US Centers for Disease Control and Prevention (CDC) on wearing masks to reduce the chances of transmitting or contracting COVID-19.
Wearing a tight-fitting surgical mask or wearing two masks can significantly reduce COVID-19 transmission and slow the spread of new, more contagious strains, according to a CDC report released Wednesday.
In a laboratory test using dummies, researchers found that wearing surgical masks that are knotted and tucked flush to the face cuts exposure to viral particles by more than 95%. Wearing a cloth mask over a surgical mask—double masking—is equally effective. But a proper fit is the key.
New guidance on the CDC website says other effective options to improve fit include adding a mask fitter—a band worn over a mask to keep it snug to the face—and wearing a nylon covering over the mask.
To see what this new guidance might mean for veterinary hospital staff, NEWStat checked in with J. Scott Weese, DVM, DVSc, DACVIM. A contributing reviewer of the 2018 AAHA Infection Control, Prevention, and Biosecurity Guidelines, Weese is also the author of a series of in-depth guides on COVID-19 safety protocols for hospitals on behalf of the Ontario Veterinary Medical Association.
And he has plenty to say about masks and COVID.
Given recent surges in COVID cases caused by new variants of the virus combined with the uncertainty surrounding vaccine efficacy against those variants, Weese told NEWStat: “We have to up our game.” He says a big part of that is getting more people to wear masks and to wear them properly. “Poor compliance with masks, distancing, and other measures is still probably the main driver of transmission.”
Weese said many media outlets seem to view the CDC’s message as a recommendation to double mask, but “It’s not really that cut and dry.” Double masking is less about adding layers than it is improving fit.
“A well-fitted single mask should be fine,” Weese says. The problem is, not all single masks fit well. “Adding a second layer increases filtering, for sure, but more importantly, it tends to help [ensure that] the primary mask is snug.” He said that two poorly fitting masks are probably much less effective than a well-fitting cloth mask, but concedes that double masking “is an easy message.”
In short, the CDC recommends wearing a well-fitting mask to help prevent COVID infection. And while there are many ways to improve mask fit, a second mask is just one option.
“Personally, I wear a well-fitting cloth mask for routine purposes,” Weese says. “In hospitals, double masking is reasonable if there’s poor compliance with ensuring good fit or if there are challenges in other protocols.”
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