1. Department of Medicine, Division of Infectious Diseases, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
2. Department of Pathology & Laboratory Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
3. Department of Clinical Epidemiology, Tan Tock Seng Hospital, Singapore
4. Department of Epidemiology, UCLA School of Public Health, Los Angeles, CA, USA
5. 4th Department of Internal Medicine, Attikon University Hospital, National and Kapodistrian University of Athens School of Medicine, Athens, Greece