1. Department of Medicine, Children’s Hospital Boston, Harvard Medical School, Boston, Massachusetts;
2. Departments of Molecular Virology and Microbiology and Pediatrics, Baylor College of Medicine, Houston, Texas;
3. Department of Pediatrics, Kosair Children’s Hospital, University of Louisville, Louisville, Kentucky;
4. Department of Emergency Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts; and
5. Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania