Widespread use of face masks in public may slow the spread of SARS CoV-2: an ecological study

Chris Kenyon

[1]. There has, however, been remarkable variation in how extensively it has spread 64 and in the national responses to this spread [1, 2] . For example, although the virus is 65 thought to have first emerged in China, European countries such as Italy and Spain 66 have reported roughly 30-fold higher number of infections per capita than China [1, 67 2]. Understanding the reasons underpinning this heterogeneity in spread is crucial to 68 ongoing prevention efforts. The cornerstones of prevention efforts have included 69 extensive testing, contact tracing and isolation and various forms of social 70 distancing/quarantining [3, 4] . Whilst there have been important differences in how 71 these were implemented in different countries, arguably the most striking difference 72 in approach has been in the use of universal face masks in public. Whereas a 73 number of predominantly Asian countries have promoted this practice, the World 74