1 Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA. Electronic address: nathan.lo@stanford.edu.
2 Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.
3 Department of Medicine, University of Toronto, Toronto, ON M5G 2C4, Canada; Divisions of Infectious Diseases and General Internal Medicine, Toronto General Hospital, University Health Network, Toronto, ON M5G 2C4, Canada.