Hong Kong CNN  — 

In the coming weeks, if they have not already, your government is likely to begin advising you to wear a face mask to protect against coronavirus.

For those living in Asia, such announcements will be a vindication of a tactic that has been adopted across much of the region since the beginning of the crisis and appears to have been borne out by lower rates of infection and faster containment of outbreaks.

In other parts of the world, this message may be confusing, coming after weeks of public health authorities, politicians and media figures confidently claiming masks do not help and urging people instead to focus on washing their hands and maintaining social distancing.

The tone of such claims ranged from condescending to frustrated, with the US Surgeon General Jerome Adams tweeting in late February – in all caps – “STOP BUYING MASKS!”

“They 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,” he added, in a post that has since been retweeted over 43,000 times.

That same week, Robert Redfield, director of the Centers for Disease Control and Prevention (CDC), appeared before lawmakers. Asked if people should wear masks, he had a straightforward answer: “No.”

Now he’s not so sure. On Monday, Redfield said told NPR that the CDC was reviewing its guidelines and may recommend general mask use to guard against community infection. It’s likely only a matter of time before other mask holdouts, most prominently the World Health Organization (WHO), follow suit.

Pivot to protection

Writing last month, Adrien Burch, an expert in microbiology at the University of California, Berkeley, noted that “despite hearing that face masks ‘don’t work,’ you probably haven’t seen any strong evidence to support that claim. That’s because it doesn’t exist.”

In fact, there is evidence of the exact opposite: that masks help prevent viral infections like the current pandemic.

Burch pointed to a Cochrane Review – a systemic analysis of published studies on a given topic – which found strong evidence during the 2003 SARS epidemic in support of wearing masks. One study of community transmission in Beijing found that “consistently wearing a mask in public was associated with a 70% reduction in the risk of catching SARS.”

SARS, like Covid-19, is a respiratory illnesses caused by the same family of viruses called coronavirus.

While SARS spread around the world, the worst of the epidemic was focused in Asia, particularly mainland China and Hong Kong. The legacy of this experience could be seen early on in the current pandemic, as news of a virus spreading led people across the region to don face masks to protect themselves.

From the beginning, Hong Kong and many other Asian governments have recommended people wear masks in public, whether they are showing virus symptoms or not.

Despite eye-rolling in some parts of the Western press, and talk of Asia’s “obsession” with face masks, the tactic appears to have contributed in helping to stem the outbreak.

Taiwan, South Korea and mainland China, all places with widespread mask use, have seen greater success in preventing major outbreaks or reining them in once they begin than in Europe and North America where masks are either not used or hard to come by.

Speaking to CNN, Ivan Hung, an infectious diseases specialist at the Hong Kong University School of Medicine, said that “if you look at the data in Hong Kong, wearing a mask is probably the most important thing in terms of infection control.”

“And it not only brings down the cases of coronaviruses, it also brings down the influenza,” he said. “In fact, this is now the influenza season, and we hardly see any influenza cases. And that is because the masks actually protected not only against coronaviruses but also against the influenza viruses as well.”