1. Department of Internal Medicine & Infectious diseases, University Medical Center Utrecht, Utrecht, The Netherlands
2. Department of Gastroenterology & Hepatology, University Medical Center Utrecht, Utrecht, The Netherlands
3. Department of Immunology, Laboratory for Translational Immunology (LTI), University Medical Center Utrecht, Utrecht, The Netherlands
4. Centre for Infectious Disease Control, National Institute for Public Health & the Environment (RIVM), Bilthoven, The Netherlands