Even experts who favor masking the masses say their impact on the spread of disease is likely to be modest. Many are also afraid to promote mask buying amid dire shortages at hospitals. But as the pandemic wears on, some public health experts thinkt government messages discouraging mask wearing should shift.

“It’s really a perfectly good public health intervention that’s not used,” argues KK Cheng, a public health expert at the University of Birmingham. “It’s not to protect yourself. It’s to protect people against the droplets coming out of your respiratory tract.”

Cheng and others stress that however masks are used, people must practice social distancing and stay at home as much as possible to prevent the spread of the novel coronavirus. When people do venture out and interact, they’re likely to spew some saliva. “I don’t want to frighten you, but when people speak and breathe and sing—you don’t have to sneeze or cough—these droplets are coming out,” he says.