1. Pediatric Oncology and Hematology, Saarland University Hospital and Saarland University Faculty of Medicine, Homburg, Germany
2. Otorhinolaryngology, Saarland University Hospital and Saarland University Faculty of Medicine, Homburg, Germany
3. Institute for Medical Biometry, Epidemiology and Medical Informatics, Saarland University Hospital and Saarland University Faculty of Medicine, Homburg, Germany
4. Center for Infectious Diseases, Institute of Medical Microbiology and Hygiene, Saarland University, Homburg, Germany