As state and federal officials continue to ramp up efforts to control the outbreak of coronavirus in the United States, new information about the virus — in particular the potential for transmission by people without symptoms — is raising new questions about the official messaging on the use of face masks during this pandemic.

In a series of tweets sent Wednesday morning, Food and Drug Administration Commissioner Scott Gottlieb suggested that evidence that the virus can be spread by asymptomatic people undermines the official position maintained by the Centers for Disease Control and Prevention that masks should only be worn by the sick.

“If the concern is that asymptomatic or mildly symptomatic younger Americans (millennials) are continuing to spread #Coronavirus because they don’t heed warnings, you could require anyone between certain ages to wear a procedure mask when they go out,” wrote Gottlieb.

Procedure masks, similar to surgical masks, are general-use medical face masks that attach to the back of the head or ears with straps and are used to catch bacteria released from the wearer’s mouth or nose.

Gottlieb pointed out the challenges involved in enforcing orders for people to remain indoors for prolonged periods of time, especially if they are asymptomatic, suggesting that “requiring a procedure mask for those who go out in areas of sustained spread (like some big cities) would be a second layer of protection when people are asymptomatic or defiant.”

“If we’re at the point of locking down entire cities, we must consider other ways to break off transmission that don't take away peoples’ liberty,” wrote Gottlieb.

If we're at the point of locking down entire cities, we must consider other ways to break off transmission that don't take away peoples' liberty. CDC's current position is that people should only wear a mask when you're sick. But we know this is spread by Asymptomatic people 2/n — Scott Gottlieb, MD (@ScottGottliebMD) March 18, 2020

Masks have been a point of contention since the beginning of the outbreak in January — with CVS, Amazon and others selling out within weeks of the virus’s spread.

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The question is confusing because there are two kinds of masks, which can serve two distinct functions: protecting the wearer from infection, and protecting those who might be infected — but not showing symptoms — from spreading the virus.

A CDC infographic makes a distinction between the two main types of barriers: surgical or procedure masks, such as the kinds Gottlieb was referring to, and respirators. Surgical masks, which are approved by the FDA, are loose-fitting, disposable masks that stop the individual who is wearing them from spreading germs. They are not fit-tested (meaning sealed to the face) and therefore do not protect against smaller airborne particles. Respirators — like the N95 — are a major step up. Tested and approved by the National Institute for Occupational Safety and Health (NIOSH), they are tight-fitting, fit-tested masks that protect against 95 percent of airborne particles.

Boxes of N95 protective masks for use by medical field personnel in New Rochelle, N.Y. (Mike Segar/Reuters)

Although many Americans have started wearing surgical masks in public, William Schaffner, an infectious disease expert at Vanderbilt University, said that’s not what they were designed for. “Simple surgical masks — other than a kind of psychological comfort — really provide little, if any, protection concerning protecting you from acquiring an infection,” Schaffner told Yahoo in an interview last month. “They’re not designed for that and they don’t function that way.”

Schaffner said that there’s a reason you may be seeing them in the doctor’s office. “If you come to a health care facility and you’re coughing or have a sore throat, a mask will be put on you,” the epidemiologist said. “That will prevent you from giving it to someone else. But having those go out in the community to protect [you] from getting it, that's not what they’re designed for.”

The World Health Organization echoed Schaffner in a video on its website. “Medical masks … cannot protect against the new coronavirus when used alone,” said Christine Francis, an infection control coordinator at the agency. “WHO only recommends the use of masks in certain cases. If you have [a] cough, fever and difficulty breathing, you should wear a mask and seek medical care. If you do not have these symptoms, you do not have to wear these masks because there is no evidence that they protect people who are not sick.”

But in response to a shortage of the N95 respirators, the CDC now concedes that a surgical mask is probably better than nothing in protecting the wearer. The advice is directed at health care professionals and others who come into contact with potentially infected individuals, but is likely to affect the behavior of civilians as well.

Until last week, the CDC was recommending that health care workers interacting with known or suspected coronavirus patients wear custom-fitted N95 protection, as well as gloves, gowns, and protective eye gear. However, updated guidance states that surgical masks “are an acceptable alternative when the supply chain of respirators cannot meet the demand.”

Dr. Deborah Birx, White House coronavirus response coordinator, with Vice President Mike Pence. (Glen Stubbe/Star Tribune via AP)

“Of course masks work — maybe not perfectly and not all to the same degree, but they provide some protection,” Zeynep Tufekci wrote in a New York Times op-ed Tuesday, arguing that the official messaging on masks may have backfired.

Tufekci, a professor of information science at the University of North Carolina, writes that attempts by the surgeon general and other health experts to prevent a nationwide mask shortage by saying that masks are not helpful for the general public but they are necessary for healthcare workers quickly “became counterproductive and may have encouraged even more hoarding because it seemed as though authorities were shaping the message around managing the scarcity rather than confronting the reality of the situation.”

“It is of course true that masks don’t work perfectly, that they don’t replace hand-washing and social distancing, and that they work better if they fit properly. And of course, surgical masks (the disposable type that surgeons wear) don’t filter out small viral particles the way medical-grade respirator masks rated N95 and above do,” wrote Tufekci. “However, even surgical masks protect a bit more than not wearing masks at all.”

A CDC spokesperson did not respond to a request for comment.

Robyn R.M. Gershon, a clinical professor of epidemiology at New York University told Yahoo News that while surgical masks "might be helpful to limit close contact spread of droplets" requiring the use of masks in public “is not really a feasible solution — there are not enough.”

Customers line up outside of a coronavirus pop-up store in Washington, D.C. (Samuel Corum/Getty Images)

Doctors have also been subject to mixed messaging when it comes to masks.

“It’s been, in a word, confusing,” said one medical resident at New York City’s Mount Sinai Hospital of the constantly changing flow of information and recommendations around coronavirus as the number of diagnoses in the United States increases.

The resident, who asked that her name not be used because she’s not authorized to speak to press, told Yahoo News that on Tuesday, “we got an email midway through the day that now all providers are required to wear surgical masks, whereas a week ago they said not to wear masks unless we’re sick” [so as not to contradict the message that masks should only be worn by sick people].

The sudden change of directive comes as hospitals around the country, including Mount Sinai, are bracing for possible supply shortages. The Mount Sinai resident told Yahoo News that, in an effort to conserve supplies, extra protective equipment, including masks, are no longer readily available for doctors and nurses as needed. As a result, she said, “a lot of times there are situations where we come in contact with someone who has symptoms, and there’s a delay in us being able to put on personal protective equipment.”

“There are definitely times where me and other residents have been exposed in the sense that we just don't have masks,” she said.

A spokesperson for Mount Sinai did not respond to a request for confirmation or comment.

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