1 From the *Infectious Diseases Unit, †Paediatric Pharmacology Department, University of Basel Children's Hospital Basel, Basel, Switzerland; ‡Department of Paediatrics, The University of Melbourne, Parkville, Australia; §Infectious Diseases Unit, Royal Children's Hospital Melbourne, Parkville, Australia; ¶Paediatric Infectious Diseases Research Group, Infection and Immunity, St George's University of London, United Kingdom; and ‖Division of Clinical Pharmacology, Children's National Health System, Washington, DC.