1. Division of Pediatric Infectious Diseases, Nationwide Children’s Hospital, Columbus, Ohio
2. Department of Pediatrics, Ohio State University College of Medicine, Columbus
3. Center for Clinical Epidemiology and Biostatistics, Department of Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia
4. Center for Pharmacoepidemiology Research and Training, Perelman School of Medicine, University of Pennsylvania, Philadelphia
5. Division of Gastroenterology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia
6. Division of Research, Kaiser Permanente Northern California, Oakland
7. Jonathan Lax Treatment Center, Philadelphia FIGHT, Pennsylvania
8. VA Connecticut Healthcare System, West Haven, Connecticut
9. Yale University School of Medicine, New Haven, Connecticut
10. VA Greater Los Angeles Healthcare System and David Geffen School of Medicine at UCLA, Los Angeles, California; and
11. Division of Infectious Diseases, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia