[1] Univ Calif San Francisco, VAMC, Infect Dis Sect, Dept Med, San Francisco, CA 94121 USA
[2] San Francisco VA Med Ctr, San Francisco, CA USA
[3] Johns Hopkins Bloomberg Sch Publ Hlth, Dept Epidemiol, Baltimore, MD USA
[4] Stroger Hosp, Dept Med, Chicago, IL USA
[5] Rush Univ, Dept Med, Chicago, IL 60612 USA
[6] Univ So Calif, Dept Prevent Med, Los Angeles, CA 90089 USA
[7] SUNY Hlth Sci Ctr, Dept Med, Brooklyn, NY 11203 USA
[8] Georgetown Univ, Med Ctr, Dept Med, Washington, DC 20007 USA
[9] Weill Cornell Med Coll, Dept Med, New York, NY USA