[1] Univ Washington, Dept Epidemiol, Box 357236, Seattle, WA 98195 USA
[2] Univ Washington, Dept Med, Seattle, WA 98195 USA
[3] Bldg Hlth Online Communities, Richmond, CA USA
[4] San Francisco AIDS Fdn, San Francisco, CA USA
[5] Ctr Dis Control & Prevent, Div STD Prevent, Atlanta, GA USA
[6] Univ Washington, Dept Global Hlth, Seattle, WA 98195 USA