Physical distancing, face masks, and eye protection to prevent person-to-person transmission of SARS-CoV-2 and COVID-19: a systematic review and meta-analysis

Physical distancing of at least 1 meter (3.3 feet) is associated with lower risk for spread of coronaviruses, according to a meta-analysis in the Lancet.

Researchers examined 44 studies on the effects of nonpharmaceutical interventions on the risk for transmitting SARS-CoV, SARS-CoV-2, and MERS-CoV in healthcare and non-healthcare settings. Risk for transmitting the viruses was lower when exposure was at 1 meter or more, compared with less than 1 meter (adjusted odds ratio, 0.18). Risk was lower with increasing distance. N95 masks provided greater protection than surgical face masks, but both were protective. Specifically for SARS-CoV-2, mask use was associated with a 60% reduced risk for infection, compared with no mask use. Eye protection was also associated with lower infection risk.

The researchers say the analysis provides “the best available evidence that current policies of at least 1 m physical distancing are associated with a large reduction in infection, and distances of 2 m might be more effective.”

https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)31142-9/fulltext