Effectiveness of Mask-Wearing on Respiratory Illness Transmission in Community Settings: A Rapid Review.

Objective: Respiratory illnesses, including coronavirus disease 2019 (COVID-19), have resulted in millions of deaths globally. Guidance on mask-wearing in community settings has been inconsistent. This review examined the effectiveness of mask-wearing on respiratory virus transmission in community settings.
Methods: A search was conducted for English language reports of randomized controlled trials of mask-wearing in the community and effect on laboratory-confirmed respiratory infections or influenza-like illness. Investigators abstracted study characteristics and assessed bias. Meta-analysis was conducted to calculate pooled risk estimates.
Results: Eleven studies were included. In 7 studies that evaluated influenza-like illness symptoms as an outcome (3029 participants), this study found mask-wearing associated with a decreased risk of influenza-like illness (overall risk ratio [RR], 0.83; 95% confidence interval [CI], 0.71 to 0.96). Studies examining laboratory-confirmed respiratory infections as an outcome (10,531 participants) showed no statistically significant association between mask-wearing and infections (RR, 1.04; 95% CI, 0.60-1.80). However, masking combined with enhanced hand hygiene was associated with a decreased risk for both influenza-like illness symptoms (RR, 0.88; 95% CI, 0.51-1.51) and laboratory-confirmed respiratory infection (RR, 0.79; 95% CI, 0.52-1.18).
Conclusions: Masking in community settings decreases transmission of influenza-like illness. Mask-wearing combined with enhanced hand hygiene reduces transmission of influenza-like illness and laboratory-confirmed respiratory infection.