Mask-wearing is the single most effective public health measure against the coronavirus, cutting incidence by 53%, according to a new global study published in the British Medical Journal.

Why it matters: The findings come as parts of the world, including D.C., increasingly loosen masking requirements, citing vaccine efficacy. Experts have warned against lifting mask mandates too soon.

What they’re saying: “This systematic review and meta analysis [of non-pharmaceutical interventions] suggests that several personal protective and social measures, including handwashing, mask wearing, and physical distancing are associated with reductions in the incidence of covid-19,” the researchers wrote.