University of Cologne - Institute of Virology, University of Cologne - Institute of Virology, University of Cologne - Institute of Virology, University of Cologne - University Hospital of Cologne, University of Cologne - Institute of Virology, University of Cologne - Institute of Medical Statistics, University of Cologne - Institute of Virology, German Center for Infection Research (DZIF), University of Cologne - Institute of Virology and Charité - Universitätsmedizin Berlin - Department of Infectious Diseases and Respiratory Medicine