Should You Wear Two Masks to Reduce the Spread of COVID-19?

Aaron S. Weinberg MD, MPhil
February 10, 2021
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Inauguration Day, January 20, 2021: The United States not only saw a new President enter the White House, but it also sparked a conversation around doubling up on protective masks against COVID-19. Many politicians wore two masks to the event as an added layer of protection because many people were standing or sitting in close proximity to one another, making it difficult to properly social distance.

The double mask discussion continued well after the ceremony, as Dr. Anthony Fauci, M.D., director of the National Institutes of Health (NIH) Allergy and Infectious Disease department, called doubling up on masks a “common sense” move when asked by reporters. And as one of his first acts as the country’s leader, President Joe Biden even signed an executive order for masks to be worn on airplanes, in airports, and on trains, busses, and federal property.

As the nation approaches 27 million coronavirus cases and nearly 500,000 deaths, hope is on the horizon. More than 42.4 million vaccines have been administered and as the vaccine roll-out continues, mask-wearing is still a strong recommendation from the Centers for Disease Control and Prevention (CDC) and medical professionals as well. This is because the vaccines are not 100% effective and the medical community is still assessing the effects of mutant strains.

However, the question still persists: How much added protection do we really get by doubling up on masks? Here’s a closer look at the subject.

Mask Wearing Proves Its Importance

There’s no shortage of research demonstrating the benefits of mask-wearing to prevent virus transmission. Studies in the U.S., Shanghai, Germany, and around the globe have shown that wearing a mask, even a low-quality one, does indeed reduce the spread of virus particles that can be released through respiration, speaking, coughing, and sneezing.

Some research has found that even the most basic microfiber materials and surgical masks have proven to have a filtration rate greater than 50%. The highest standard when it comes to face coverings is the N-95 mask, developed and manufactured by 3M, which guarantees to filter out 95% of all airborne particles.

One scientific brief published by CDC found that multi-layer cloth masks can both block up to 50-70% of these fine droplets and particles.

A study analyzed a variety of cloth masks and found a wide range of particle removal efficiency, between 28% and 91%. Loose fit can be part of the reason, the study noted. Using a surgical mask with a close-fitting cloth mask together, however, could bring ≥ 90% particle filtration, close to the protection found in an N-95 mask.

The study, published in the medical journal, Matter, found standard medical-type masks, (the S-1 or S-3 varieties) has a removal efficiency range between 50% and 75%. But researchers found that if these masks were tightly fitted to the face and a nylon overlay was added, the coverage achieved 86% to 90% mean removal efficiency.

Which Two Are Best?

While the CDC does not explicitly recommend wearing two masks, the agency is all about being extra cautious. According to current guidelines, when selecting a mask, choose one that has two or more layers of washable, breathable fabric.

Now, if you are considering double-masking, Linsey Marr, a virus transmission expert at Virginia Tech, recommends members of the public start with a simple surgical mask, then add a snug face-hugging cloth mask on top of it. This way the surgical mask acts as a filter and the cloth mask improves fit and adds an additional layer of filtration. A maximum layer of protection involves a three-layer approach with two cloth masks and a filter layer between them; however, for the general public wanting to improve protection, the first suggestion should be sufficient.

In a February 10, 2021, report, the CDC also recommended that "fitting a cloth mask over a medical procedure mask, and knotting the ear loops of a medical procedure mask and then tucking in and flattening the extra material close to the face" helps with making sure the double mask stays fit and "substantially improved" exposure.

You also want to pay close attention to your ability to breathe with two masks on. There are some diminishing returns reported when using more than one mask that already has good filtration capabilities, and if doubling up on masks restricts breathing significantly, you should go back to using one mask or try different types of two-mask combinations that might be better for your breathing. In addition, you want to avoid heavy materials, such as vinyl, that might make for difficulty breathing and opt for materials considered safe for masks by the CDC. And if you have underlying respiratory conditions, it's important to check with your physician before double masking.

When Should I Do It?

Since the CDC has not instituted a formal recommendation on double-masking, the first priority is to always wear one mask. With a growing number of new strains of the COVID-19 virus emerging and health officials still learning about vaccine efficacy against them, double-masking is certainly a sound precaution to take particularly if you plan to be in close proximity to people not in your immediate household. Going into places like grocery stores or convening in small groups with people outside your bubble are examples of situations where double-masking is appropriate.

At the same time, if you are outdoors exercising, walking, or enjoying another activity where you are not near others, a single mask is enough. It’s a good idea to always have one handy in case you encounter others. Above all, regardless of whether you choose to wear one or two masks, you should still adhere to CDC recommended social distancing guidelines, wash your hands often, and avoid touching your face.

And finally, be careful with how you handle all masks when removing them from the face, as the outside covering may potentially have virus particles on it. You'll want to place the mask in a safe place, making sure not to touch your face when you remove it, and wash your hands or use hand sanitizer immediately after taking the mask off.

Do you like what you’ve read? If you want to learn more about Carbon Health or other health issues, download the Carbon Health app or visit carbonhealth.com.

Aaron S. Weinberg MD, MPhil

Aaron S. Weinberg, MD, MPhil, is Director of Program Development at Carbon Health and triple board-certified in Pulmonary, Critical Care, and Internal Medicine.


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