Effects of Face Mask Mandates on COVID-19 Transmission in 51 Countries: Retrospective Event Study

Anatol-Fiete Näher   ^{1, 2, 3} , MA, MD, Dr med ;   Matthias Schulte-Althoff   ^{2, 4} , MSc ;   Marvin Kopka   ^{2, 5} , MSc ;   Felix Balzer   ² , MSc, MD, PhD, Dr med ;   Francisco Pozo-Martin   ⁶ , MSc, PhD

¹ Digital Global Public Health, Hasso Plattner Institute, University of Potsdam, Potsdam, Germany

² Institute for Medical Informatics, Charité - Universitätsmedizin, Berlin, Germany

³ Method Development, Research Infrastructure, and Information Technology, Robert Koch Institute, Berlin, Germany

⁴ Department of Information Systems, School of Business and Economics, Freie Universität, Berlin, Germany

⁵ Department of Psychology and Ergonomics, Technische Universität Berlin, Berlin, Germany

⁶ Evidence-based Public Health Unit, Center for International Health Protection, Robert Koch Institute, Berlin, Germany