MASKS and SPREAD of respiratory viruses

… Antiviral drugs and vaccines may be insufficient to prevent their spread

… We included randomised controlled trials (RCTs)

… We included 11 new RCTs and cluster-RCTs (610,872 participants) in this update

… bringing the total number of RCTs to 78

… Six of the new trials were conducted during the COVID-19 pandemic

… 12 trials (10 cluster-RCTs) comparing medical/surgical masks versus no masks to prevent the spread of viral respiratory illness

… Wearing masks in the community probably makes little or no difference to the outcome of influenza-like illness (ILI)/COVID-19 like illness compared to not wearing masks

… little or no difference to the outcome of laboratory-confirmed influenza/SARS-CoV-2 compared to not wearing masks

… The use of a N95/P2 respirators compared to medical/surgical masks probably makes little or no difference for the objective and more precise outcome of laboratory-confirmed influenza infection

… Restricting pooling to healthcare workers made no difference to the overall findings

… been published and observed that medical/surgical masks were non-inferior to N95 respirators in a large study of 1009 healthcare workers in four countries providing direct care to COVID-19 patients

… The pooled results of RCTs did not show a clear reduction in respiratory viral infection with the use of medical/surgical masks

… There were no clear differences between the use of medical/surgical masks compared with N95/P2 respirators in healthcare workers when used in routine care to reduce respiratory viral infection