1. From the Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University, Stanford, and the Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, San Francisco — both in California (N.C.L.); and the Department of Epidemiology of Microbial Diseases and the Public Health Modeling Unit, Yale School of Public Health, New Haven, CT (G.S.G.).