CDC: Doubling up on masks increases protection

Universal masking is recommended to slow the spread of COVID-19. And cloth masks and medical-procedure masks substantially reduce exposure from infected wearers, as well as reduce exposure of uninfected wearers. But now the Centers for Disease Control and Prevention (CDC) has stated that wearing a medical-procedure mask under a cloth mask can block 92.5 percent of potentially infectious particles.

The agency conducted experiments to assess two ways of improving the fit of medicalprocedure masks and found each modification substantially improved source control and reduced wearer exposure.

For optimal protection, it’s now recommended to knot the ear loops of a medical-procedure mask, then tuck in and flatten the extra material close to the face before fitting a cloth mask over a that mask.

These experiments highlighted the importance of good fit to maximize mask performance.

Two important ways to make sure your cloth mask works the best it can:

• Make sure your mask fits snugly against your face. Gaps can let air with respiratory droplets leak in and out around the edges of the mask.

• Pick a mask with layers to keep your respiratory droplets in and others’ out. A mask with layers will stop more respiratory droplets from getting inside your mask or escaping from your mask if you are sick.

Do consider the following when choosing a mask:

• Choose a mask with a nose wire. A nose wire is a metal strip along the top of the mask that will prevent air from leaking out of the top of the mask. Bend the nose wire over your nose to fit close to your face.

• Use a mask fitter or brace. Use a mask fitter or brace over a disposable mask or a cloth mask to prevent air from leaking around the edges of the mask.

• Check that it fits snugly over your nose, mouth and chin.

Check for gaps by cupping your hands around the outside edges of the mask. Make sure no air is flowing from the area near your eyes or from the sides of the mask. If the mask has a good fit, you will feel warm air come through the front of the mask and may be able to see the mask material move in and out with each breath.

• Add layers of material. You can use a cloth mask that has multiple layers of fabric, or you can wear one disposable mask underneath a cloth mask. The second mask should push the edges of the inner mask against your face.

• Make sure you can see and breathe easily.

Though more and more people are being inoculated against the virus, it remains a valuable precaution to wear masks, wash hands thoroughly and often, and to maintain social distance.

—Centers for Disease Control and Prevention