CDC: Double Masking Increases Protection from COVID-19
For months, public health officials have stressed the importance of universal mask-wearing to slow the spread of COVID-19. Now, a new study from the U.S. Centers for Disease Control and Prevention suggests wearing two masks offers more protection than just one.
The CDC conducted lab tests with dummies to assess two ways to improve the fit of medical procedure masks: 1) wearing a cloth mask over the medical procedure mask (double masking) and 2) knotting the ear loops of the medical procedure mask then tucking and flattening the extra material close to the face (“knotting and tucking”). The study published February 10 found both methods improved the fit of the mask and reduced exposure to potentially infectious aerosols by as much as 95 percent when both parties wore tightly fitted masks.
New Mask Recommendations
In light of the new research, the CDC released these new recommendations to maximize mask performance:
- Choose a mask with a nose wire. A nose wire -- a metal strip along the top of the mask -- allows you to fit the mask close to your face and prevents air from leaking out the top of the mask.
- Use a mask fitter or brace over a disposable or cloth mask. A mask fitter can be solid or elastic and can be secured with head ties or ear loops. Studies have shown these small, reusable devices improve fit and prevent air from leaking out. The CDC provides an illustration of a mask fitter here.
- Make sure your mask fits snugly over your nose, mouth and chin. There should be no gaps around the outside edges. Gaps can let air containing respiratory droplets leak in and out.
- Wear multiple layers of material. Either use a cloth mask with multiple layers of fabric or wear a disposable mask under a cloth mask. It is important to note that the CDC does not recommend wearing two disposable masks because doing so will not improve fit. The CDC also says you should not wear another mask over a KN95 mask.
- Use the knot and tuck method to create a better fit. Knot the ear loops of a 3-ply mask where they join the edge of the mask. Fold and tuck the extra material around the edges. Here is a Pro Tip to help your Earloop Mask Fit More Tightly
The key with all of the above recommendations is fit. The better the mask fits, the more protection it offers.
Slowing the Spread
The number of new coronavirus cases is trending downward, but health officials warn now is not the time to ease up on restrictions like mask wearing and social distancing. There is concern that new variants of COVID-19 could cause cases to spike again. Two variants first identified in the United Kingdom and South Africa are now circulating worldwide and both are highly transmissible.
Vaccination efforts continue to ramp up across the country, but it will be some time before we achieve herd immunity from vaccines. Until that happens, masking, social distancing, and frequent handwashing are our best defenses.
In our next blog, we will look at some of the reasons why masking and social distancing are necessary even after you receive your vaccination.