They performed a systematic review and meta-analysis to investigate the optimum distance for avoiding person-to-person viral transmission and to assess the use of face masks and eye protection to prevent transmission of viruses. Data for SARS-CoV-2 and betacoronaviruses that cause severe acute respiratory syndrome, and Middle East respiratory syndrome from 21 standard WHO-specific and COVID-19-specific sources were obtained. The findings of this systematic review and meta-analysis support physical distancing of 1 metre or more and provide quantitative estimates for models and contact tracing to inform policy. Optimum use of face masks, respirators, and eye protection in public and healthcare settings should be informed by these findings and contextual factors. The authors concluded that robust randomised trials are needed to better inform the evidence for these interventions, but the systematic appraisal of currently best available evidence reported in the paper might inform interim guidance.
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