With hospitals in dire need of face masks and other equipment to keep them from contracting the coronavirus, President Donald Trump suggested an alternative for Americans who also want protection in public: Wear a scarf.
"It doesn't have to be a mask," Trump said at a press briefing Tuesday night. "You can use scarves. You can use something else over your face."
The following evening, Trump repeated that advice, claiming without evidence that scarves are "highly recommended by the professionals."
"Depending on the fabric, I think in a certain way a scarf is better," Trump claimed.
There is currently little empirical evidence to back up Trump's recommendation that a scarf or other covering can substitute for a face mask.
Doctors told CNBC that there are pros and cons to using masks, makeshift or otherwise, in public.
"As far as the general public is concerned, the do-it-yourself option of wearing a scarf or bandana may be the best we can do at this point," said Dr. William Schaffner, medical director of the National Foundation for Infectious Diseases.
Dr. Angela Hewlett of the Infectious Diseases Society of America said that wearing a scarf or bandana could protect others from the spread of the coronavirus. It might also keep people from touching their faces, she said.
"A scarf acts sort of like a handkerchief or a tissue," Hewlett said. "If you're wearing a scarf around your face, or another homemade mask, then there's a chance that your secretions will be contained in that as opposed to being spread to the environment."
Still, the doctors stressed that there is limited evidence that wearing alternative coverings in public can prevent transmission of COVID-19.
"We don't know" if they can work nearly as well as other masks, such as N95 respirators or other protective equipment built specifically to filter airborne particles, Hewlett said.
Trump said Tuesday evening that "my feeling is, if a lot of people want to do it, there is certainly no harm to it."
"Use a scarf if you want, rather than going out and getting a mask or whatever," he said. "We're making millions and millions of masks, but we want them to go to the hospitals."
But both doctors said that masks could engender a "false sense of security," making people less likely to follow preventative measures that have proven more effective – namely, washing hands regularly, staying at home as much as possible and keeping a safe distance from others.
Hewlett added that it could be counterproductive: "It may make people more likely to reach up and adjust the bandana or the scarf or their mask or whatever, especially if you're not used to wearing that type of thing."
The Centers for Disease Control and Prevention website says that the agency "does not recommend the routine use of respirators outside of workplace settings." A spokesman told CNBC on Wednesday morning that the CDC had not updated its guidance in the wake of Trump's comments.
But The Washington Post, citing a federal official, reported Tuesday that the CDC is considering whether to recommend that all Americans wear face masks.
"There may be a role for face masks in this situation," Hewlett said. "At this point there's not a lot of medical data to support it, but we're at a point where we're seeing this widespread transmission and we really need to do something to try to stop it."
Schaffner said that "the bottom line message should be: stay 6 feet apart and wash your hands."
-- CNBC's Tucker Higgins and Dan Mangan contributed to this report.