1. From the Pediatric Infectious Disease Sections of Baylor College of Medicine, Houston, Texas;
2. University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania;
3. University of Southern California School of Medicine, Los Angeles, California;
4. Wake Forest University School of Medicine, Winston-Salem, North Carolina;
5. Children's Hospital San Diego, San Diego, California;
6. Ohio State University College of Medicine and Public Health, Columbus, Ohio;
7. Northwestern University Medical School, Chicago, Illinois; and
8. University of Arkansas for Medical Sciences, Little Rock, Arkansas.