1. Vanderbilt University School of Medicine, Nashville, Tennessee, USA
2. University of Texas Health Science Center at Houston, Houston, Texas, USA
3. Indiana University School of Medicine, Indianapolis, Indiana, USA
4. Johns Hopkins University, Baltimore, Maryland, USA
5. Mid-Atlantic Permanente Research Institute, Rockville, Maryland, USA
6. University of California, San Diego, San Diego, California, USA
7. Kaiser Permanente Northern California, Oakland, California, USA
8. Retrovirus Research Center, Universidad Central del Caribe, Bayamón, Puerto Rico, USA
9. University of British Columbia, Vancouver, British Columbia, Canada
10. Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
11. University of Alabama at Birmingham, Birmingham, Alabama, USA
12. University of Calgary, Calgary, Alberta, Canada
13. McGill University, Montreal, Quebec, Canada
14. University of Washington, Seattle, Washington, USA
15. Emory University School of Medicine, Atlanta, Georgia, USA
16. Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee, USA