Can wearing a face mask protect you from the new coronavirus?

Editor's Note: On April 3, the Centers for Disease Control and Prevention began recommending that people wear face coverings in public. You can read that coverage here. The below article was written before this recommendation was issued.

Can wearing a medical face mask protect you against the new coronavirus? It's a question many people are asking, including pet owners who are putting canine face masks on their dogs. 

If it's a regular surgical face mask, the answer is no, Dr. William Schaffner, an infectious disease specialist at Vanderbilt University in Tennessee, told Live Science. 

A more specialized mask, known as an N95 respirator, can protect against the new coronavirus, also called SARS-CoV-2. The respirator is thicker than a surgical mask, but neither Schaffner nor the Centers for Disease Prevention and Control (CDC) recommend it for public use, at least not at this point.

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That's because, in part, it's challenging to put on these masks and wear them for long periods of time, he said. 

Specialists receive retraining annually on how to properly fit these respirators around the nose, cheeks and chin, ensuring that wearers don't breathe around the edges of the respirator. "When you do that, it turns out that the work of breathing, since you're going through a very thick material, is harder. You have to work to breathe in and out. It's a bit claustrophobic. It can get moist and hot in there," Schaffner said.

"I know that I can wear them when I need to for about a half-hour," he added. "But then, I have to go out of the isolation room, take it off and take some deep breaths, kind of cool off, before I can go back in."

While it still might be possible to snag an N95 respirator online, Schaffner advised against it. If too many people unnecessarily stockpile respirators, a shortage could put the health of medical workers and those who need them at risk, Schaffner said.

Updated March 5 with the latest information on COVID-19.

Surgical masks

The thinner surgical mask is intended for surgeons, because these products do a good job of keeping pathogens from the doctor's nose and mouth from entering the surgical field, Schaffner said. 

In some Asian countries, such as Japan and China, it's not uncommon to see people wearing surgical masks in public to protect against pathogens and pollution. But those masks don't help much in the context of a virus, Schaffner said. "They're not designed to keep out viral particles, and they're not nearly as tightly fitted around your nose and cheeks" as an N95 respirator, he said.

"Could they be of some use? Yes, but the effect is likely to be modest," Schaffner said.

He noted that some people wear surgical masks because they are sick with a cold or the flu and they don't want to get other people sick. But if you're sick, it's best just not to go to public areas. "That's the time to stay home," Schaffner said.

People sick with COVID-19, however, should wear face masks to reduce the risk of infection to people around them, according to the CDC. Health care workers and those "taking care of someone infected with COVID-19 in close settings (at home or in a healthcare facility)," should also wear face masks, the CDC reported. 

People wearing surgical masks should dispose of them after each use, the CDC added. 

Otherwise, the best way to avoid getting the coronavirus is to, first and foremost, postpone any travel to places with known outbreaks. You can also thoroughly wash your hands with soap; avoid touching your eyes, nose and mouth with unwashed hands; avoid close contact with people who are sick; and disinfect frequently touched objects and surfaces, the CDC recommends. 

As for pet owners putting face masks on their dogs, a Pomeranian dog in Hong Kong  tested positive a "weak positive" for COVID-19. That dog is now in quarantine, but is not showing symptoms of the disease, according to a March 5 piece in the South China Morning Post. However, it's unclear how the dog was tested for the illness. What's more, it doesn't appear that pets can transmit the virus to humans, and experts told people with pets not to panic.

Rather than put face masks on pets, the CDC advises that people ill with COVID-19 avoid animals, just as they would other people. 

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Originally published on Live Science.