Since initial reports of novel coronavirus (known in public health circles by the unsexy moniker Covid-19) started surfacing earlier this year, the response on social media has ranged widely from measured caution to unmitigated panic. Global stocks have plummeted, and although cases in China are falling, at least 7,048 people have tested positive for coronavirus in the United States, with at least 116 patients dying from the illness.

As Angela Rasmussen, a virologist who serves on the faculty at the Center for Infection and Immunity at Columbia University’s school of public health,...