Winter is back, and so are warnings from "experts" for Americans to don masks. A resurgence of influenza (flu) and respiratory syncytial virus (RSV)—respiratory illnesses that took a holiday during the Covid-19 pandemic, when various measures limited person-to-person contact and spread of disease—is allegedly combining with new Covid cases into a so-called tripledemic, leading academics and public-health officials to advise masking. An advisory from the New York City health commissioner instructs that "everyone . . . should wear a mask" at all times when indoors and when in a crowded outdoor setting. While the advisory says that "higher-quality masks, such as KN95 and KF94 masks and N95 respirators, can offer an additional layer of protection," it does not otherwise distinguish between types of masks or discourage cloth masks. And Los Angeles County is, again, encouraging people to wear masks in indoor public spaces.

Can mask mandates be far behind? Let's hope not. The need for masks is far from clear, and mandates could be counterproductive.