Why Not Just Tell Everyone to Wear Masks?

The C.D.C.’s advice about masking up again was not easy to parse. Some experts think simpler would have been better.

An internal presentation circulated within the Centers for Disease Control and Prevention last month, and eventually obtained by news organizations, offered clear advice for countering the contagious Delta variant: “Given higher transmissibility and current vaccine coverage, universal masking is essential.” But the recommendation issued by the agency was considerably more nuanced, advising Americans, vaccinated or not, to wear masks in indoor public settings in areas with “substantial” or “high” virus transmission. At the time, that included at least 80 percent of Americans. As infection rates soar, some experts are now wondering: Would it have made more sense just to call for everyone to mask up?