Health experts won’t ask Americans to take off their masks any time soon. That’s the take of Eric Toner, a senior scholar at the Johns Hopkins Center for Health Security. He has been preparing for an outbreak like the novel coronavirus as part of his work for years. [cut] “I think that mask wearing and some degree of social distancing, we will be living with — hopefully living with happily — for several years,” he said. “It's actually pretty straightforward. If we cover our faces, and both you and anyone you're interacting with are wearing a mask, the risk of...