Summary
Of 2,616 records, 79 studies of mask wearing or mask policies in real-world settings met the criteria (search to June 2023). 61 of them (77%) reported that masks or mask policies reduced SARS-CoV-2 transmission or COVID-19, with similar shares across study designs, mask types and settings.
Key points
- Of 2,616 records, 79 studies met the criteria: 43% in community settings, 38% in health care and 19% in schools or universities.
- 61 studies (77%) reported evidence that mask wearing or mask policies reduced SARS-CoV-2 transmission or COVID-19.
- The share reporting benefit was similar across study designs (67% to 100%), mask types (77% to 100%) and settings (80% to 91%); 85% of masking-policy studies reported a benefit.
- The review counted studies for or against an effect (vote counting) rather than pooling effect sizes.
- Design: systematic review following PRISMA guidelines, searched to June 2023.
- Funding: Conrad Prebys Foundation and NIMHD (NIH); no conflicts declared.