But medical experts say the effectiveness of masks at preventing the spread of the coronavirus is limited. Many of the masks people are wearing do little to protect them, and even the most effective have to be fitted and worn properly to have any benefit.
 
They can even be harmful if the discomfort of wearing them leads people to touch their faces or a potentially contaminated mask more frequently.
 
“The likelihood that any of these are going to protect anyone in these environments is minimal,” said Bruce Ribner, medical director of Emory University Hospital’s Serious Communicable Diseases Unit. “Wearing these things can in some ways be worse than not wearing one.”

Medical experts say the best ways for people to avoid infection are to wash their hands often, and avoid touching their eyes, mouths and noses.