Surgical masks were designed to keep medical personnel from inadvertently infecting patients’ wounds, not to prevent the spread of viruses. Public-health officials’ advice in the early days of Covid-19 was consistent with that understanding.
Fast-forward 15 months. Rand Paul has been suspended from YouTube for a week for saying, “Most of the masks you get over the counter don’t work.” Many cities across the country, following new CDC guidance handed down amid a spike in cases nationally caused by the Delta variant, are once again mandating indoor mask-wearing for everyone, regardless of inoculation status. The CDC further recommends that all schoolchildren and teachers, even those who have had Covid-19 or have been vaccinated, should wear masks.
How did mask guidance change so profoundly? Did the medical research on the effectiveness of masks change—and in a remarkably short period of time—or just the guidance on wearing them?
In truth, the CDC’s, U.K.’s, and WHO’s earlier guidance was much more consistent with the best medical research on masks’ effectiveness in preventing the spread of viruses. That research suggests that Americans’ many months of mask-wearing has likely provided little to no health benefit and might even have been counterproductive in preventing the spread of the novel coronavirus.