1. Institute of Medical Microbiology and Infection Control, Hospital of the Johann Wolfgang Goethe-University, Frankfurt, Germany
2. Institute of Medical Virology, Hospital of the Johann Wolfgang Goethe-University, Frankfurt, Germany
3. Institute of Occupational, Social and Environmental Medicine, Friedrich-Schiller-University, Jena, Germany
4. Health Protection Authority, City of Frankfurt am Main, Frankfurt, Germany
5. Occupational Health Service, Hospital of the Johann Wolfgang Goethe-University, Frankfurt, Germany