[1] Univ Calif San Francisco, Epidemiol & Prevent Intervent Ctr, San Francisco, CA 94143 USA
[2] Univ Calif San Francisco, San Francisco Gen Hosp, Epidemiol & Prevent Intervent Ctr, Div Infect Dis, San Francisco, CA 94143 USA
[3] Univ Calif San Francisco, San Francisco Gen Hosp, Epidemiol & Prevent Intervent Ctr, Posit Hlth Program, San Francisco, CA 94143 USA