[1] Univ Washington, Dept Epidemiol, 325 Ninth Ave,HMC 359931, Seattle, WA 98104 USA
[2] Statens Serum Inst, Copenhagen, Denmark
[3] Univ Washington, HIV STD Program, Publ Hlth Seattle & King Cty, Seattle, WA 98104 USA
[4] Univ Washington, Dept Med, Seattle, WA 98104 USA
[5] Univ Washington, Dept Global Hlth, Seattle, WA 98104 USA
[6] Univ Washington, Dept Biostat, Seattle, WA 98104 USA