[1] Univ Washington, Dept Med, 325 Ninth Ave,Box 359777, Seattle, WA 98104 USA
[2] Publ Hlth Seattle & King Cty, HIV STD Program, Seattle, WA USA
[3] Washington State Dept Hlth, Off Infect Dis, Olympia, WA USA
[4] Univ Washington, Dept Epidemiol, 325 Ninth Ave,Box 359777, Seattle, WA 98104 USA