1. From the Department of Pediatrics, Uniformed Services University of the Health Sciences, Bethesda, Maryland;
2. Department of Pediatrics, Walter Reed Army Medical Center, Washington, DC;
3. Department of General Pediatrics and Adolescent Medicine, Children's National Medical Center, Washington, DC;
4. Department of Pediatrics, George Washington University School of Medicine and Health Sciences, Washington, DC; and
5. Holy Cross Hospital, Silver Spring, Maryland.