1. Institute for Virology, Ulm University Medical Center, Ulm, Germany
2. Institute for Clinical Transfusion Medicine and Immunogenetics Ulm, German Red Cross Blood-Transfusion Service Baden-Württemberg–Hessen and University Hospital, Ulm, Germany
3. Institute for Virology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
4. Institute for Transfusion Medicine, Ulm University, Ulm, Germany