From a purely mathematical perspective, face masks are more effective in reducing the transmission of COVID-19 than we may think. This happens for two reasons: masks protect in both directions (when we breathe in and when we breathe out), and the number of interactions involving people wearing masks is higher than the number of people wearing masks in public.

This video, that is supported by the Science program and produced by Minute Physics, has attracted more than one million viewers in its first week of being online, and explains how wearing face masks can make a drastic difference in the fight against COVID-19.