1. Department of Infectious Diseases, Kaiser Permanente San Francisco, San Francisco, CA;
2. Division of Research, Kaiser Permanente Northern California, Oakland, CA;
3. Kaiser Permanente Information Technology, Pleasanton, CA;
4. Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, MA;
5. Division of Infectious Diseases, Beth Israel Deaconess Medical Center, Boston, MA; and
6. Department of Adult and Family Medicine, Kaiser Permanente San Francisco, San Francisco, CA.