Do face masks reduce coronavirus infections?
• Debate shifts in Europe and US over use of protective gear long employed in Asia as authorities have rethink
IT MIGHT BE THAT WEARING A MASK IS EQUALLY AS EFFECTIVE OR MORE EFFECTIVE THAN DISTANCING
Western countries have begun to embrace the mass public use of face masks to combat coronavirus in a growing trend that mimics long-standing anti-pandemic measures in parts of Asia.
Austria followed Slovakia, the Czech Republic and BosniaHerzegovina by saying it would be compulsory for people to wear the protective gear outside the home, even though the World Health Organisation (WHO) does not recommend such a move.
In a sign that the debate was shifting, New York mayor Bill de Blasio last week urged citizens to wear face masks or even home-made coverings when they were outside.
This came after the US Centers for Disease Control and Prevention said it was reconsidering whether to recommend face gear to the public, rather than only those caring for a sick person.
The Financial Times looks at the scientific, cultural and behavioural factors behind the shift in attitudes towards masks, as the pandemic continues to sweep the globe.
CLINICAL TESTS
Most experts agree that wearing a face mask can stop some virus-laden watery droplets that are thought to be a main coronavirus vector and are expelled into the air when a person coughs, sneezes or just breathes out.
More contentious is whether they help reduce the risk of a person becoming infected by inhaling the virus through their nose or ingesting via the mouth.
A big problem in resolving the debate conclusively has been the lack of proper clinical trials on the effect of masks on viral infection rates. Such tests are difficult to conduct because of the large number of variables, says Paul Hunter, professor in medicine at Britain’s University of East Anglia.
He said less rigorous studies of flu did suggest some benefits to mask wearers.
These are hard to quantify but they could include that wearing a mask prevents you from touching your mouth or nose directly and infecting yourself with viruses picked up from surfaces.
“My own view is that the balance of evidence is pointing towards some protective effect,” said Hunter. “You have to be careful about poor-quality evidence. But it is not no evidence.”
Yet some authorities are holding firm to recommendations for the public not to use them.
“Wearing face masks to prevent coronavirus infection only makes sense in hospitals where patients with the coronavirus are treated and in laboratories where specimens of these patients are tested,” states the official advice of Belgium’s Federal Public Service for Health. “For the time being, wearing face masks in public places has no added value at all.”
SAFETY IN NUMBERS
Proponents of masks say their primary value is less to protect the wearer than to prevent that person from infecting others. They help curb the spread of droplets by breathing, coughing or sneezing in crowded environments such as public transport. They can also help stop the contamination of surfaces and goods on supermarket shelves.
In many European countries, official advice has concentrated on the need for hand hygiene and for people to maintain social distancing of 2m.
But David Heymann, chair of a WHO advisory panel on infectious hazards, said he was considering new research, including a Massachusetts Institute of Technology study, suggesting droplets from sneezes can travel up to 8m.
“It might be that wearing a mask is equally as effective or more effective than distancing,” Heymann told the BBC, with the caveats that the new evidence needed to be supported and masks should be properly fitted by users.
Some experts argue that donning facial protection is on one level an act of wider civic duty that only becomes effective when it is widely observed. “I wear a mask to protect you; you wear a mask to protect me,” said KK Cheng, professor of public health at the UK’s University of Birmingham. “At the end, everyone is protected if enough people do it.”
WESTERN RELUCTANCE
One reason for Western authorities’ caution about recommending the mass wearing of masks has been a concern about shortages that has already prompted many countries to increase local manufacturing and scour the world for extra supplies.
On April 2, Taiwan pledged to donate 10-million face masks to countries hit hard by the coronavirus pandemic, including EU member states and the US.
Even proponents of face protection discourage members of the public from using highgrade gear such as N95 respirators. Surgical masks normally sold in shops have also been in short supply in many places, leaving the alternative of simple cloth masks.
Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases, said the country had been “inhibited” from encouraging mask-wearing because it did not want to “take away the supply of masks from the health-care workers who need them”.
The shift by De Blasio urging people to wear face masks or similar coverings was aimed at slowing the spread of the virus in a city that has become the epicentre of the outbreak in the US.
“We are advising New Yorkers to wear a face covering when you go outside and will be near other people,” the mayor said at a media conference on Thursday. “It could be a scarf, it could be a bandanna, something you create yourself. It does not need to be a professional surgical mask.”
The balance is shifting as the pandemic grows in Western countries and governments cast around for whatever measures they can find to try to quell it.
Sebastian Kurz, Austria’s chancellor, acknowledged mask-wearing was culturally “alien” but said the country had to do everything possible so it could “quickly return to normalcy and a functioning economy”.
The changing policies in some European countries move them closer to the positions of Asian counterparts.
While citizens in Western countries such as the US did resort to face protection when the Spanish flu pandemic ripped across the globe in 1918, maskwearing fell away again once the threat receded.
Many Asian countries, by contrast, have been sensitised by being on the front line of outbreaks of dangerous diseases, notably the severe acute respiratory syndrome (SARS) virus in the early 2000s.
FLU SEASON
In China, where the outbreak began, people have been wearing masks to protect themselves from the virus for several months. Chinese President Xi Jinping began wearing a mask in public in early February.
In Taiwan and other parts of Asia, experts say the public habit of mask-wearing during flu seasons has proved beneficial during the Covid-19 pandemic.
“If the objective is to prevent the spread of the virus to other people, there is no option but to wear a mask,” said Kazunari Onishi, author of The Dignity of Masks and associate professor at St Luke’s International University in Tokyo.
Masks are not a substitute for other measures to quell the spread of the virus, such as large-scale testing, physical distancing and regular hand washing.
Face gear also needs to be changed regularly to avoid contamination: a particular potential problem in poor countries, where people lack the means to buy new masks or clean old ones.
The protection’s effectiveness can also fall away with repeated washing.
While some observers, including President Donald Trump, have suggested fashioning home-made protective gear from items such as scarves, experts say such ersatz creations are less effective at stopping droplets. They can also become damp and thus a potential vector for infection because they lack the inner water absorbent layer used in surgical masks.
Asked about Trump’s scarf idea, Chen Shih-chung, Taiwan’s health minister, said the protection offered would be “very poor”.
But he added, in words that appear to be increasingly persuasive to health authorities in the West: “Anything is better than nothing”. /©