Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said that when it comes to wearing two masks to protect against the coronavirus, it "makes common sense" that more than one layer of masking would be more effective.
There is no specific research on how well face coverings work against new variants of the virus, including the more transmissible variant from the United Kingdom that has been detected in at least 22 states in the United States.
A mask "is a physical covering to prevent droplets," Fauci said Monday on NBC's "TODAY" show. "So, if you have a physical covering with one layer, you put another layer on, it just makes common sense that it likely would be more effective."
Asked at a White House briefing last week whether the new variant would make masks less effective, he said that on the contrary, the variants are "the reason why you absolutely should be wearing a mask."
Dr. Marybeth Sexton, an assistant professor of infectious diseases at the Emory University School of Medicine in Atlanta, agrees with Fauci's view.
The new variants "may lead people who have them to have a higher amount of virus in their nose, in their mouth, so that when they breathe or talk or cough or sing, they may put more viral particles out in the environment than the average person," she said.
But, Sexton added, "that should not be a huge problem if everybody has a mask on."
If worn correctly, face coverings are expected to help prevent the spread of any respiratory virus, no matter the variant.
"If that wasn't plainly obvious six months ago, it surely is now," said Cameron Wolfe, an infectious diseases expert and an associate professor of medicine at the Duke University School of Medicine.
Which mask should you wear?
The key is to strike a balance between comfort and effectiveness.
"If you put three or four masks on, it's going to filter better because it's more layers of cloth," said Dr. Scott Segal, chair of anesthesiology at Wake Forest Baptist Health in Winston-Salem, North Carolina. "But you'll be taking it off because it's uncomfortable."
Segal has been studying face covering fabrics for much of the past year in response to the pandemic. Overall, he said, 3-ply medical-grade surgical masks tend to offer the best protection for the average individual.
For those opting for cloth masks, Segal recommends "two layers of high-quality cotton material with a relatively high thread count."
Acceptance of face coverings has come a long way over the past year. Americans increasingly use them as a way to make fashion statements or to show love for their favorite sports teams.
Accordingly, the mask-making industry has exploded with little oversight. There is no standardized tool — such as one that's equivalent to a nutrition facts label on food — for consumers looking to gauge mask quality.
Technically, the Food and Drug Administration regulates masks, including cloth face coverings, but only when they are marketed specifically for "medical purposes." Most companies do not explicitly advertise their products as such (in fact, many state that their masks are not for medical use), putting the onus on consumers to decide which might offer the most protection.
The gold standard N95 mask is not recommended for the average person, according to the Centers for Disease Control and Prevention, and instead should be reserved for health care professionals.
"You could have a very good N95 mask, but let's say that somebody isn't wearing it properly or is only wearing it 50 percent of the time," said Dr. Leana Wen, an emergency physician and former health commissioner for Baltimore. "I would rather that someone wear a surgical mask or cloth mask 100 percent of the time, correctly and consistently."
Last year, the FDA authorized the Chinese version of the N95, called KN95, for emergency use. However, counterfeit versions of KN95s have flooded the market. The National Institute for Occupational Safety and Health, part of the CDC, has a detailed, visual list of knockoff brands.
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One easy way to test cloth masks at home is to hold it up to a light. If light shines in between the cloth's individual fibers, it probably means that viral particles can get through, too, Segal said.
His research, which has not yet been peer-reviewed or published in a journal, has also found that adding a piece of flannel between layers of cotton may also be an effective way to filter viral particles. That can be added to masks that come with an opening in the middle so users can insert an additional filter.
Segal did not recommend using coffee filters or industrial grade vacuum filters, citing a lack of evidence they work well to filter viral particles appropriately. Other filters, such as PM2.5 filters, won't block viral particles, but can be counted as an additional layer in a mask.
No matter what type of mask is used, the most important thing is to wear it correctly.
"I worry more about people wearing masks down on their chins, not covering their mouths and noses, than I do about what the mask is made of," said Dr. Richard Besser, president of the Robert Wood Johnson Foundation and a former acting director of the CDC.
Indeed, "the best quality mask is frankly the one that you wear the right way for the longest amount of time when you're interacting with other people," Wolfe, of Duke University, said.
Face coverings should extend from the top of the nose to the chin without gaps on the sides.
"If your nose is sticking out, it's entirely useless," Segal said.
Other tips include:
- Avoid masks with a valve. Segal said that while the valve allows for easier breathing, it defeats the purpose of wearing a mask because it lets viral particles out, putting others at risk
- Keep extra masks on hand in case one breaks or becomes soiled
- Hard plastic face shields should not used be a substitute for cloth or medical-grade masks, according to the CDC.