2023 CR Forum Top Ten| Impact of community masking on COVID-19

A growing body of scientific evidence suggests that face masks can protect against COVID-19. There was, however, limited rigorous evidence on the extent to which mask-wearing is effective in reducing COVID-19 in a real-life situation with imperfect and inconsistent mask use. While masks had been promoted as a front-line defense against the worldwide spread of COVID, there was doubt, both scientifically, and in public and political spheres as to their value as worn in real life, and little discussion of the quality of different kinds of masks. It was thought to be practically and ethically impossible to obtain high-quality randomized evidence from real-world situations. In Bangladesh, the study team partnered with Bangladeshi policymakers and a local NGO to design and evaluate various strategies to increase mask-wearing and assess the impact of community mask-wearing on SARS-CoV-2 infection rates. They found that a four-part intervention (the NORM model) tripled mask usage (a 29- percentage-point increase), and increased physical distancing by 5 percentage points. Further, this increase in mask-wearing reduced symptomatic SARS-CoV-2 infections. When surgical masks were employed, 1 in 3 symptomatic infections were avoided for individuals 60+ years old, the age group that faces the highest risk of death following infection. This was the first large-scale randomized evaluation to demonstrate the effectiveness of masks in a real-world setting.