The Impact of Community Masking on COVID-19: Study
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Mask usage remains low across many parts of the world during the COVID19 pandemic, and strategies to increase mask-wearing remain untested. The objectives were to identify strategies that can persistently increase mask-wearing and assess the impact of increasing mask-wearing on symptomatic SARS-CoV-2 infections.


The team conducted a cluster-randomized trial of community-level mask promotion in rural Bangladesh from November 2020 to April 2021 (N=600 villages, N=342,126 adults). All intervention arms received free masks, information on the importance of masking, role modeling by community leaders, and in-person reminders for 8 weeks.

The control group did not receive any interventions. Outcomes included symptomatic SARS-CoV-2 seroprevalence (primary) and prevalence of proper mask-wearing, physical distancing, and symptoms consistent with COVID-19 (secondary). Mask-wearing and physical distancing were assessed through direct observation at least weekly at mosques, markets, the main entrance roads to villages, and tea stalls.

At 5 and 9 weeks follow-up, we surveyed all reachable participants about COVID-related symptoms. Blood samples collected at 10-12 weeks of follow-up for symptomatic individuals were analyzed for SARS-CoV-2 IgG antibodies.


There were 178,288 individuals in the intervention group and 163,838 individuals in the control group. The intervention increased proper mask-wearing from 13.3% in control villages to 42.3% in treatment villages. This tripling of mask usage was sustained during the intervention period and two weeks after. Physical distancing increased from 24.1% in control villages to 29.2% in treatment villages. After 5 months, the impact of the intervention faded, but mask-wearing remained 10 percentage points higher in the intervention group.

The proportion of individuals with COVID-like symptoms was 7.62% in the intervention arm and 8.62% in the control arm. Blood samples were collected from N=10,952 consenting, symptomatic individuals. Adjusting for baseline covariates, the intervention reduced symptomatic seroprevalence by 9.3%. In villages randomized to surgical masks (n = 200), the relative reduction was 11.2% overall and 34.7% among individuals 60+. No adverse events were reported.


Our intervention demonstrates a scalable and effective method to promote mask adoption and reduce symptomatic SARS-CoV-2 infections.