How good is the evidence that mandatory mask laws reduce transmission?
A recent study by a German non-profit economic think-tank compared regions in Germany that implemented mandatory mask laws at different times (before the entire country made masks mandatory in stores and transit on April 27). The study, which was published on the group’s website but not in a peer-reviewed journal, suggested mask laws could reduce the daily growth rate of reported infections by 40 per cent.
Other studies show that masks do reduce the rate at which sick people shed the virus and the distance droplets travel from your mouth. Mathematical modelling studies also suggest that universal mask wearing can be used to control epidemics.
Advocates of universal mask wearing note that countries with widespread or mandated mask use, such as South Korea, Taiwan, China and the Czech Republic, have seen reduced cases and fatalities, although that may be due to other factors.