The public assumes that research performed since the beginning of the pandemic supports mask mandates. Policy makers and the media point to low-quality evidence, such as a study of Covid-19 positive hairstylists in Missouri or a Georgia summer camp with an outbreak. These anecdotes, while valuable, tell us nothing about the experience of other hairdressers or other summer camps that adopted similar or different masking practices. Also low-quality evidence: Videos of droplets spreading through air as people talk, a well-intended line of research that has stoked fears about regular human interactions.
[Editor’s note: Dr. Ladapo is an associate professor at UCLA’s David Geffen School of Medicine.]
Rather, the highest-quality evidence so far is studies like the one published in June in Health Affairs, which found that U.S. states instituting mask mandates had a 2% reduction in growth rates of Covid-19 compared with states without these mandates. Because respiratory virus spread is exponential, modest reductions can translate into large differences over time. But these shifts in trajectory are distinct from the notion that mandating masks will bring the pandemic to an end. Based on evidence around the world, it should be clear that mask mandates won’t extinguish the virus.
The most reasonable conclusion from the available scientific evidence is that community mask mandates have—at most—a small effect on the course of the pandemic.