Medical experts have urged people to stop panic buying face masks, warning that such equipment is not an effective way to protect yourself from the fast-spreading coronavirus.
The advice comes at a time of intensifying concern about COVID-19, which has killed more than 3,000 people worldwide since late last year.
The outbreak was first identified in Hubei province, China, where over 90% of the deaths have been reported. More recently, the virus has been spreading at a faster rate outside China than inside the country.
The WHO has declared the outbreak a global health emergency, with almost 60 countries reporting cases of the coronavirus.
Epidemiologists and infectious disease experts have been at pains to emphasize against an unwarranted scramble for face masks in recent weeks, particularly because such hoarding behavior elevates the prospect of an equipment shortage for medical workers.
"Seriously people — STOP BUYING MASKS!" U.S. Surgeon General Jerome Adams said via Twitter over the weekend.
"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!"
The warning from America's top doctor is consistent with medical advice from the U.S. Centers for Disease Control and Prevention, which has said there is no evidence to support wearing face masks.
Instead, Adams said "the best way to protect yourself and your community is with everyday preventative actions, like staying home when you are sick and washing hands with soap and water, to help slow the spread of the respiratory illness."
It has been suggested wearing face masks could be useful if you're sick in order to prevent you from sneezing or coughing into somebody's face, David Heymann, who led WHO's infectious disease unit at the time of the SARS epidemic in 2002-2003, said at a Chatham House press briefing last month.
But, "a mask that is used to stop getting an infection is sometimes not very effective because people take it off to eat, many times they are worn improperly (and) if they get wet and somebody sneezes on that mask it could pass through.
So, there is really not a lot of evidence (to support wearing masks)."
"One of the most important ways of stopping respiratory outbreaks such as this is washing hands," Heymann continued.
That's because "if you touch a patient, if you shake hands, if you touch a door that has a droplet on it — which could theoretically happen — then you touch your face (or) your mouth and you become infected."
"So, handwashing is the most important. And second is, people who are suspected as being patients, be very careful when you are dealing with them. Avoid face-to-face contact and wash hands when you're treating," Heymann said.
"It is very important that people understand that they can prevent themselves from being infected if they follow a few simple measures," he added.
South Korea, Italy and Iran have all recorded sharp upticks in cases of the coronavirus in recent days, with many other countries imposing travel restrictions on virus-hit areas worldwide.
Infections have now been reported in every continent except Antarctica.
Emily Landon, medical director for infection control at the University of Chicago Medical Center, told CNBC late last week that face masks were "not a great choice" for everyday use.
"First of all, there are multiple different kind of face masks. There is the surgical mask that people wear that doesn't really seal up very well. That's super good if you put it on the patient who's sick because that will contain their secretions and protect everyone around them."
"However, if you are the one who wants to protect yourself, those N95 masks … are much better," Landon said.
"You need to be fit-tested in order to know exactly which size you should be wearing, you have to be trained on how to wear it properly and they can get pretty uncomfortable, so they are not a great choice for just going out in the public," she continued.
"Keeping your hands clean so that you don't touch your face no matter what things you are touching with your hands is a really important piece of preventing infection in hospitals, in schools and everywhere you go."
"Soap and water works really well. It can dry your hands out a little bit more but when you do it, you want to do it right. That means getting your hands wet with warm water, cleaning them, getting all of the surfaces with soap for 20 seconds — that's a full time through 'Happy Birthday' — and then also rinsing them off afterwards," Landon said.