Does wearing a mask while traveling ward off illness? Here's what experts say

What started off as a viral infection only in China is now spreading.

What started off as a viral infection only in China in December is now spreading throughout Asia and has made its way to the United States. The novel coronavirus -- "2019-nCoV"-- in the same class as the SARS and MERS viruses, is now linked to thousands of deaths and has infected hundreds of hundreds more worldwide as it continues to spread.

Transportation has been shut down in Wuhan, China, and neighboring cities. Five major U.S. airports have started mandatory screenings for direct and indirect flights from Wuhan including John F. Kennedy in New York, Los Angeles International Airport, San Francisco International, Hartsfield-Jackson in Atlanta and Chicago O’Hare International Airport.

With the recent outbreak, images from across the world show people wearing masks to ward off illness when traveling. However, wearing a mask is not a practice the Centers for Disease Control and Prevention recommends for preventing infection in healthy travelers.

There is little benefit to wearing a surgical type mask, and may even put you at greater risk for spreading infection, infectious disease doctors told ABC News.

"There isn’t a lot of data to support if there is any benefit to wearing a mask in the public setting. It is currently unclear," advised Dr. Jonathan Grein, a board-certified infectious disease physician and director of Hospital Epidemiology at Cedars-Sinai Medical Center in Los Angeles. He says masks are used by doctors and nurses when dealing directly with sick people. "We use them in the health care setting for two main reasons: to contain secretions of individuals who have respiratory infections and to protect healthcare workers providing direct care to patients."

If a patient starts to develop symptoms, a surgical mask has been shown to limit spreading germs, which is not only polite but could help limit a dangerous outbreak.

"Many respiratory viruses are spread by large respiratory droplets which are filtered by surgical masks," said Dr. Henry Wu, assistant professor of infectious disease at the Emory University School of Medicine and former medical epidemiologist at the CDC. "If someone has a cold or the flu or another viral respiratory infection, wearing a simple mask will decrease the risk of that person spreading infection."

Health care professionals and those in direct contact with the sick are advised to wear N95 medical respirator masks. These masks are rated for higher protection.

"Industrial masks [for example, ones worn for construction] or other occupational respirators are not designed for healthcare use or infection control. Medical N95 respirators are only recommended for health care personnel that are fit-tested and trained in their use," says Dr. Wu.

"With N95 respirators, if you wear them properly, the work of breathing is very difficult and should not be worn for a long time," said Dr. William Schaffner, professor of preventive medicine and infectious disease at Vanderbilt School of Medicine and medical director of National Foundation of Medical Diseases. "Painter’s masks are very flimsy and aren’t any good for preventing someone from respiratory infection. The CDC is very skeptical for these reasons."

But what about passengers on trains and planes trying to avoid getting sick during cold and flu season or during an outbreak like the coronavirus?

"Masks are not recommended for general protection if you are not ill," said Wu.

There may even be a risk to wearing a mask preventively.

"The mask itself can become contaminated and serve as a source of infection actually doing more harm than good," said Grein. "If wearing a mask, I caution touching it."

Instead, he advises, "avoid travel if you are ill, sneeze or cough into your sleeve and not your hand, and always washing your hands frequently."

"It’s also very important to get the flu shot," he said to protect yourself and those around you.

The CDC recommends following its current guidelines for safe travel during the coronavirus outbreak which include:

- Avoid contact with sick people.
- Avoid animals (alive or dead), animal markets, and products that come from animals (such as uncooked meat).
- Wash hands often with soap and water for at least 20 seconds. Use an alcohol-based hand sanitizer if soap and water are not available.
- Older travelers and those with underlying health issues may be at risk for more severe disease and should discuss travel to Wuhan with their healthcare provider.
- Medical personnel in the hospital taking care of sick patients should use contact precautions and wear an N95 disposable face piece respirator.

John Smith, M.D., is a psychiatry resident from Medical University of South Carolina and a member of the ABC News Medical Unit