NEW YORK (CBS) At first, health officials said masks were only necessary for health care workers and sick patients. Mayors from major cities including New York and Los Angeles are now urging residents to cover their noses and mouths if they must go out in public during the coronavirus pandemic.
"We want to make sure that anyone that doesn't have to get it, doesn't get it. So a face covering is just a simple way to protect other people and to reduce the speed of that community spread," said Mayor Bill de Blasio, D-New York City.
Dr. David Agus is a CBS News medical contributor. He says the change in thinking about covering our faces comes from more understanding of this new virus.
"The days before you get symptoms you can spread the virus and also people never have symptoms. Those people from the droplets of their mouths when they breathe or cough can spread the virus," Agus said. "What it does is it protects other people so you won't spread the virus even if you don't know you have it."
This new guidance doesn't mean you should cover up with a medical-grade mask. You can use any piece of cloth like a scarf or bandana.
When giving his recommendation, Los Angeles Mayor Eric Garcetti emphasized: "Notice I haven't called them masks. That's because N95 and other medical-grade masks like surgery masks are reserved for medical workers like doctors and nurses. And using an N95 mask yourself, if you're not one of them, could cost a doctor or a nurse their life."
Health officials emphasize other basic hygiene remains critical now more than ever. Wash your hands constantly, cover your cough and sneeze, and stay home especially if you are sick.
Symptoms of coronavirus may appear two to 14 days after exposure.