This gives a good overview over the current state of scientific research wrt mask usage in general: https://www.nature.com/articles/d41586-020-02801-8 https://w

This gives a good overview over the current state of scientific research wrt mask usage in general: https://www.nature.com/articles/d41586-020-02801-8 https://www.nature.com/articles/d41586-020-02801-8 tl:dr: Some indicators point to masks being useful but the data isn't conclusive and a lot of other factors might impact the data (such as other covid-19 related measures that help in keeping infection rates low) but these two quotes should be sufficient reason to wear them: “There’s a lot more we would like to know,” says Vos, who contributed to the analysis. “But given that it is such a simple, low-cost intervention with potentially such a large impact, who would not want to use it?” It’s not the only solution, says Gandhi, “but I think it is a profoundly important pillar of pandemic control”. As Digard puts it: “Masks work, but they are not infallible. And, therefore, keep your distance.”