Letter to the Editor: Meta-analysis on facemask use in community settings to prevent respiratory infection transmission shows no effect

"We read with interest the systematic review and meta-analysis by Chaabna et al. aiming at synthesizing the available evidence on the effectiveness of facemasks to prevent the transmission of respiratory infections in the community setting. The authors reported an apparent benefit of facemasks use, which showed a significant reduction in the risk of influenza, influenza-like illness, severe acute respiratory syndrome coronavirus (SARS-CoV), and SARS-CoV-2 transmission (pooled OR = 0.66, 95% confidence interval: 0.54–0.81). However, there are several methodological flaws in the study that might have led to misleading conclusions...

Based on the ten clinical trials included in the meta-analysis, we reviewed and reanalyzed the data to compare whether the use of facemask as a sole intervention was associated with the transmission of respiratory infections in the community setting... there were no significant differences between medical facemasks use only and controls in the odds of developing laboratory-confirmed influenza and influenza-like illness. Similarly, no differences in laboratory-confirmed influenza risk were observed when comparing mask use solely versus the combined intervention of face mask and handwashing, indicating that facemask as the sole intervention in the community is not associated with reducing respiratory infection."