Division of Infectious Diseases, Department of Medicine, Stanford University, Stanford, CA, USA. robjgiff@gmail.com|Division of Infectious Diseases, Department of Medicine, Stanford University, Stanford, CA, USA. robjgiff@gmail.com|Division of Infectious Diseases, Department of Medicine, Stanford University, Stanford, CA, USA. robjgiff@gmail.com|Division of Infectious Diseases, Department of Medicine, Stanford University, Stanford, CA, USA. robjgiff@gmail.com|Division of Infectious Diseases, Department of Medicine, Stanford University, Stanford, CA, USA. robjgiff@gmail.com|Division of Infectious Diseases, Department of Medicine, Stanford University, Stanford, CA, USA. robjgiff@gmail.com|Division of Infectious Diseases, Department of Medicine, Stanford University, Stanford, CA, USA. robjgiff@gmail.com