1. Department of Pediatrics, School of Medicine, University of Pittsburgh and Children’s Hospital of Pittsburgh, Pittsburgh, Pennsylvania;
2. Department of Health Care Policy, Harvard Medical School, Harvard University, Boston, Massachusetts;
3. RAND Corporation, Boston, Massachusetts;
4. Division of Infectious Diseases, Boston Children’s Hospital, Boston, Massachusetts;
5. Department of Emergency Medicine, Brigham and Women’s Hospital, Boston, Massachusetts;
6. RAND Corporation, Arlington, Virginia; and
7. Division of General Medicine and Primary Care, Beth Israel Deaconess Medical Center, Boston, Massachusetts