An Analysis of public data on SARS-CoV-2 infections in Germany suggests that in regions that mandated the use of face masks in public spaces had registered lower infections.
The analysis suggested that by 20 days after the implementation of such mandates had approximately 45 percent lower infections compared to other large cities that did not implement mask mandates.
The results suggest that face masks might be a cost-effective method for preventing COVID-19.
Scientists used the synthetic control method to analyze the effect of face masks on the spread of COVID-19 in Germany.
The identification approach of researchers exploited regional variation in the point in time when wearing face masks became mandatory in public transport and shops.
Depending on the region, researchers found that face masks reduced the number of newly registered severe acute respiratory syndrome coronavirus 2 infections between 15 percent and 75 percent over a period of 20 days after their mandatory introduction.
Assessing the credibility of the various estimates, scientists conclude that face masks reduce the daily growth rate of reported infections by around 47 percent.