WASHINGTON — Testifying on Capitol Hill on Feb. 28, Dr. Robert Redfield could not be more clear. “There is no need for these masks in the community,” Dr. Redfield said of the N95 masks that were then becoming the subject of intense focus, with the coronavirus outbreak having arrived on the West Coast of the United States.
“These masks need to be prioritized for health care professionals,” Redfield added. Coming from the director of the Centers for Disease Control and Prevention, this pronouncement had the weight of an official directive. So even as images of people in Asian countries wearing masks proliferated, the vast majority of Americans remained mask-free.
Just a little over a month later, the CDC has changed its mind. During Friday’s briefing of the White House coronavirus task force, President Trump said that all Americans should wear some sort of face covering when venturing outside.
That announcement is the culmination at the highest levels of government of debate over a question far less simple than it seems: Does putting something over your face keep you safe from infection?
Trump said on Friday that the guidance was not mandatory and that he would not follow it himself, suggesting that it would be unseemly to don protective gear in the Oval Office. Nor will the federal government provide face masks to Americans who wish to wear one. “Most people could just make something,” he said, “out of a certain material.” He had previously suggested using scarves.
On its coronavirus page, the CDC now recommends that everyone “should wear a cloth face cover when they have to go out in public, for example to the grocery store or to pick up other necessities.” The page also explains that a mask or face covering is not bound to protect the wearer; instead, the mask will protect others in case the wearer is sick. Wearing a mask, then, is less an act of personal protection than of altruism.
The new guidance comes just two days after public health authorities in Singapore published a study about the role of “presymptomatic transmission.” That takes place when a person who has been infected with the coronavirus but not yet showing symptoms of COVID-19 (the disease caused by the coronavirus) continues on with their daily life. In doing so, they could unintentionally spread the virus to many others.
Wearing a mask would keep that person from releasing viral droplets when they sneeze or cough. If everyone in the United States were to wear a mask, whether surgical or makeshift, when coming into contact with others, presymptomatic transmission would likely be reduced.
The Singapore study found that presymptomatic transmission usually occurred between one and three days before a person started showing the telltale signs of COVID-19, which include a dry cough, shortness of breath and a high fever. The study also found that in China, where the coronavirus originated, presymptomatic transmission accounted for about one out of eight instances of viral spread.
“We now know from recent studies that a significant portion of individuals with coronavirus lack symptoms,” explained U.S. Surgeon General Jerome Adams at the Friday press conference where administration officials announced that they were recommending Americans wear masks. But at the end of February, he had urged the exact opposite. “STOP BUYING MASKS!" he wrote on Twitter the day after Dr. Redfield testified before Congress.
Adams went on to argue that masks “are NOT effective in preventing general public from catching #Coronavirus, but if healthcare providers can’t get them to care for sick patients, it puts them and our communities at risk!”
In a sense, he remains correct in that assertion. It will fall to him and other public health authorities in the coming days to explain just what the new guidance means. Those efforts could be frustrated by Trump himself, who described the new guidance on Friday as “a voluntary thing.”
Epidemiologists have been working furiously for months to understand the pathogenesis of the coronavirus: that is, how it manages to enter the human body, and what it does once it lodges there. The new guidance is, if anything, a testament to just how much science has come to understand about the virus known formally as SARS-CoV-2.
Early in the coronavirus outbreak, coverage of the face mask question tended to give credence to the belief that the wearer might behave with a false sense of security endowed by wearing one. “The masks don’t give a hermetic seal, so very small drops of the virus suspended in the air can still get through,” one article from January explained.
That remains true: The masks do not protect the wearer as much as they might seem to. But other considerations are at work. As scientists have deepened their understanding of the coronavirus, they have realized that viral droplets can remain airborne for longer than initially thought.
A study published earlier this month in the New England Journal of Medicine found that viral particles “can remain viable in aerosols for multiple hours,” perhaps for as many as three. That makes it imperative to keep those particles from becoming airborne in the first place.
There is also the critical difference between viral droplets and virus-bearing bioaerosols that emanate from a person’s mouth when they simply exhale. Scientists are coming to the conclusion that spread through bioaerosols is possible, given experiences of doctors at the University of Nebraska. Those experiences were detailed in a letter sent by the National Academies of Sciences, Engineering, and Medicine to the White House’s Office of Science and Technology Policy on April 1.
In issuing the new guidance, the CDC has had to balance the need to protect the general public with concerns about resource hoarding. Authorities across the country have moved swiftly in recent days against individuals who have amassed private stockpiles of personal protective equipment in hopes of selling supplies at a significant profit.
Respirator masks are desperately needed in hospitals that have been overwhelmed by COVID-19 patients. But now that people have been urged to wear facial protection by the CDC, it will be more difficult to keep them from trying to seek out respirators and face masks on the private market.
The New York Times recently devoted a full page to showing people how to sew face masks of their own.
Many people in Asia have long worn such masks as a matter of routine, especially when traveling, and have faced social stigma for doing so. Now, however, that practice appears to have been vindicated.
“It’s a civic duty,” one Chinese student living in New York told Time magazine earlier this month. “If I have a mask on,” she explained, “I could cut the chain off where I am. That could save a lot of people.”
Click here for the latest coronavirus news and updates. According to experts, people over 60 and those who are immunocompromised continue to be the most at risk. If you have questions, please reference the CDC and WHO’s resource guides.