London – Wearing face masks, which health officials in many countries previously discouraged outside hospitals, is gaining converts as the coronavirus spreads across the globe.
So far, U.S. and international health authorities have mostly relied on virus-fighting measures such as physical distancing, while recommending frequent hand-washing. Masks, they’ve said, may serve little purpose among untrained users and should be prioritized for sick people and those looking after them.
Yet evidence that the stealthy coronavirus can spread in people with no symptoms is forcing officials to consider broader protective measures to stem a pandemic that’s killed more than 54,000 people, crippled health systems and gouged economies.
While evidence is inconclusive, “it’s just common sense that a mechanical barrier must do something,” said Annalies Wilder-Smith, a professor of emerging infectious diseases at the London School of Hygiene and Tropical Medicine, who recommends using masks to prevent transmission in the home.
The shift in thinking comes as many people across the U.S. and Europe have already adopted the practice — widespread in Asia since the SARS epidemic of 2003 — when they venture out of confinement for visits to the supermarket or jogs around the park. Any call for broader use could further squeeze availability of masks for health care workers, as supplies have run short in some countries.
U.S. President Donald Trump said health officials are recommending the use of nonsurgical grade cloth masks as a voluntary measure to prevent the spread of the coronavirus, but that he did not plan to wear on himself. “It’s only a recommendation,” he told reporters at the White House on Friday.
Masks are most likely to help in cases when it’s difficult or impossible to stay six feet away from others, such as at a pharmacy, Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases, said April 3 in an interview with Fox News.
An expert panel advising the the World Health Organization will review new evidence on masks Friday and make a recommendation to the agency for consideration this week, said David Heymann, an epidemiologist who chairs the committee and oversaw the WHO’s response to the 2003 outbreak of SARS (severe acute respiratory syndrome).
Support for masks is spreading from the U.S. West Coast to the Czech Republic. California is recommending that people wear them when shopping, or other situations where keeping a safe distance from others is difficult. Czech citizens have been ordered to wear them outside the home since March 18.
Although questions remain about the broader public arena, multiple studies have shown that masks can help stem disease spread in areas where the likelihood of transmission is high, like college dormitories and households, said Raina MacIntyre, an epidemiologist at the University of New South Wales in Sydney.
“If it protects in high-transmission settings it should also protect in crowded public settings like public transport,” she said in an email, “and also in lower-transmission settings such as walking down the street.”
Decisions on the issue will likely include considerations such as availability of masks for health workers and for sick people. Countries including the U.S. and the U.K. are struggling to keep adequate supplies, and thousands of doctors and nurses have been infected, some fatally. New recommendations could also drive up prices, putting them further out of the reach of some care providers.
A university hospital in Grenoble, France, triggered a social-media uproar last month when it sent doctors and nurses a tutorial on how to sew their own four-layered protective masks. The hospital management said it was a measure of last resort for health workers who wouldn’t be directly caring for COVID-19 patients.
Cloth masks could stop someone with the illness from infecting others but wouldn’t prevent the wearer from getting sick, said Lothar Wieler, president of the Robert Koch Institute, Germany’s public health authority.
“These masks shouldn’t give a false sense of security,” he said at a news conference last week.
A study published April 3 in Nature showed that surgical masks of the flat, paper variety can also reduce emission of virus-carrying droplets from the nose and mouth. The study suggests that the masks “could be used by ill people to reduce onward transmission,” the authors wrote.
Doctors, nurses and other health professionals sometimes use tighter-fitting respirators that are designed to keep pathogens out.
Guidelines should not be changed until the supply issue is solved, Wilder-Smith said. But in the meantime, countries should turn their attention to producing millions of masks and educating people in how to use them properly, she said.
Websites such as maskssavelives.org have sprung up touting the advantages of masks. Nassim Taleb, author of the “The Black Swan: The Impact of the Highly Improbable,” has come out in favor of masks, while criticizing the WHO for hesitating to recommend them. Cases are growing more slowly in areas where masks are used routinely — South Korea, Hong Kong, Singapore and Japan — Taleb said on Twitter.
“This is the strongest statistical association I’ve seen with respect to the virus,” he said in the tweet.
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