People line up outside a COVID-19 testing site in the Brooklyn borough of New York on Jan 2, 2021. (KENA BETANCUR / AFP)

The US Centers for Disease Control and Prevention, or CDC, may soon recommend wearing two masks－one over the other－to enhance protection against the coronavirus, said Anthony Fauci, the nation's top infectious disease expert.

Fauci and the CDC discussed the possibility on Monday, but the agency does not yet have the data to make any formal recommendation, the expert said on Tuesday in a livestreamed interview with The Washington Post.

Still, "it makes common sense" to increase protection, Fauci said.

"The CDC makes recommendations based on data that they accumulate because it's a science-based organization, the CDC," Fauci said on Wednesday during a White House COVID-19 briefing. "Right now, they're looking at these different options of mask-wearing."

Although the CDC has not yet outlined specific guidelines regarding wearing two masks to prevent the spread of the virus, Fauci said he often double masks.

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If you add on another mask, you may actually make it tougher for the air to move through the two-cloth area, ... it causes more air to actually leak around the sides, which actually enhances your ability to get infected.

Michael Osterholm, an infectious disease expert

Concerns remain

There are some concerns the practice could cause more harm if one is not worn correctly.

Michael Osterholm, an infectious disease expert who was an adviser to US President Joe Biden's transition team, said problems can occur with masks that have an "already compromised fit or filtration capacity", allowing respiratory droplets to escape out of holes.

"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," he told NBC on Sunday.

Separately, Iowa Democrats decided to wear jeans on the state House floor all week to protest the lack of a mask mandate. Members are banned from wearing jeans on the floor.

"I told the chief clerk, jeans aren't hurting anybody but all the people wandering around without masks on, they are," Democratic Representative Beth Wessel-Kroeschell said on Wednesday.

Neither the Iowa House nor Senate allow members or staff on the floor of the chambers to wear jeans or T-shirts, while the House rules encourage but do not require mask-wearing.

The pandemic has killed over 100,000 people in the country this year, a tally by Johns Hopkins University said.

At the same time, Fauci also warned the coronavirus could spread further if people hold or attend Super Bowl parties on Sunday when the football game is on TV.

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Xinhua contributed to this story.

Contact the writer at minluzhang@chinadailyusa.com