Getting to the Truth About the Effectiveness of Masks in Preventing COVID-19

Chou and Dana reported the final update of a living systematic review that addresses the effectiveness of masks in preventing SARS-CoV-2 infection. The editorial discusses the findings, why there is disagreement about the effectiveness of masking interventions, and the types of studies that will be necessary to arrive at more certain answers about whether and under what conditions masking interventions prevent transmission of SARS-CoV-2.