1 Division of Pediatric Infectious Diseases, Children's National Hospital; Department of Pediatrics, The George Washington University School of Medicine and Health Sciences.
2 Division of Pediatric Infectious Diseases, Children's National Hospital; Department of Pediatrics, The George Washington University School of Medicine and Health Sciences; Department of Microbiology, Immunology, and Tropical Medicine, The George Washington University School of Medicine, Washington, District of Columbia. Electronic address: rdebiasi@childrensnational.org.