Earlier this month The Lancet (Medical Journal) published the most comprehensive study to date providing evidence on physical distancing and face masks to prevent the spread of COVID-19.
- First review of all available evidence including 172 observational studies looking at how physical distancing, face masks, and eye protection affect the spread of COVID-19, SARS, and MERS in both community and healthcare settings across 16 countries.
- Physical distancing of at least 1 metre lowers risk of COVID-19 transmission, but distances of 2 metres could be more effective.
- Importantly, even when properly used and combined, none of these interventions offers complete protection and other basic protective measures (such as hand hygiene) are essential to reduce transmission.
It appears, keeping at least one metre from other people as well as wearing face coverings and eye protection, in and outside of health-care settings, could be the best way to reduce the chance of viral infection or transmission of COVID-19,
The currently best available evidence suggests that COVID-19 is most commonly spread by respiratory droplets, especially when people cough and sneeze, entering through the eyes, nose, and mouth, either directly or by touching contaminated surfaces.
Analysis of data from nine studies (across SARS, MERS and COVID-19, including 7,782 participants) looking at physical distance and virus transmission found that keeping a distance of over one metre from other people was associated with a much lower risk of infection compared with less than one metre (risk of infection when individuals stand more than a metre away from the infected individual was 3% vs 13% if within a metre).
Evidence from 10 studies (across all three viruses, including 2,647 participants) also found similar benefits for face masks in general (risk of infection or transmission when wearing a mask was 3% vs 17% when not wearing a mask). Evidence in the study was looking mainly at mask use within households and among contacts of cases, and was also based on evidence of low certainty.
Professor Raina MacIntyre writes in reference to the study (not part of the study); "[They] also report that respirators and multilayer masks are more protective than are single layer masks. This finding is vital to inform the proliferation of home¬made cloth mask designs, many of which are single¬layered. A well designed cloth mask should have water¬resistant fabric, multiple layers, and good facial fit...Universal face mask use might enable safe lifting of restrictions in communities seeking to resume normal activities and could protect people in crowded public settings and within households."
Let's do our part, wash our hands frequently, keep our distance from each other in public places and wear our masks.