1. Department of Medicine, University of California (UC), San Francisco , San Francisco, California , USA
2. Department of Medicine, Johns Hopkins University , Baltimore, Maryland , USA
3. The Fenway Institute and Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School , Boston, Massachusetts , USA
4. Department of Medicine, University of Washington , Seattle, Washington , USA
5. Division of Infectious Diseases, University of Alabama at Birmingham , Birmingham, Alabama , USA