[1] Johns Hopkins Univ, Berman Inst Bioeth, Baltimore, MD 21205 USA
[2] Johns Hopkins Univ, Dept Med, Baltimore, MD USA
[3] Fred Hutchison Canc Res Ctr, Vaccine & Infect Dis Div, Seattle, WA USA
[4] HIV Prevent Trials Network Leadership & Operat Ct, Washington, DC USA
[5] Inst Nacl Infectol Evandro Chagas, Rio De Janeiro, Brazil
[6] UCLA, Ctr Clin AIDS Res & Educ, Los Angeles, CA USA