Top infectious diseases expert says double masking may actually increase COVID infection: 'May do more harm'

Michael Osterholm, an infectious disease expert, said Sunday that wearing two face masks as a precautionary measure against the coronavirus may actually increase the chances of becoming infected.

What's the background?

As public health experts fear the spread of potentially more contagious COVID-19 variants, Dr. Anthony Fauci endorsed last week the practice of "double masking" — wearing a cloth face covering over a surgical face mask.

Speaking on NBC's "Today" show last week, Fauci called double masking "common sense."

"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 and that's the reason why you see people either double masking or doing a version of an N-95," Fauci said.

But what is Osterholm saying?

Osterholm, who served on President Joe Biden's COVID-19 Advisory Board during the presidential transition, explained on NBC's "Meet The Press" that double masking could enhance infection.

"When we talk about double masking, remember what we're really talking about is just trying to prevent the virus from being excreted by me into the air or me inhaling the virus from someone else in the air, and it's both a function of face fit and face filtration," Osterholm said.

Osterholm, who is the director of the Center for Infectious Disease Research and Policy at the University of Minnesota, used swimming goggles as an analogy to explain the downside to double masking.

"Think about your swim goggles. When's the last time anybody leaked at the lenses? They leak at the fit," Osterholm began.

"So, what we're concerned about is that many of these face cloth coverings do have already compromised fit or filtration capacity," he continued. "If you add on another mask, you may actually make it tougher for the air to move through the two cloth area, and then at that point, it causes more air to actually leak around the sides, which actually enhances your ability to get infected."

In fact, Osterholm claimed that double masking may do "more harm" than good.

I'm not saying that some couldn't be used in a better way. But at the same time, there are many that actually, you may do more harm. Let me just say right now one thing that's really, to me, very important is we see up to 25% of people who wear it under their nose. You know, that's like fixing three of the five screen doors in your submarine. You know, what's going on there? We've got to get people to start using these right. That would help right there tremendously.

Full Osterholm: 'We Need To Get As Many One-Doses … As We Possibly Can" | Meet The Press | NBC Newswww.youtube.com

The Centers for Disease Control and Prevention has not yet issued guidance about double masking.

Current CDC guidance says that cloth face masks (as opposed to the disposable paper kind) should "have two or more layers of washable, breathable fabric" and should "fit snugly against the sides of your face and don't have gaps."

Meanwhile, Fauci, who is Biden's chief medical adviser, has since backtracked on double masking being "common sense."

"There's no data that indicates that that is going to make a difference," Fauci said of double masking.