[1] Univ Coll Cork, Dept Epidemiol & Publ Hlth, Cork, Ireland
[2] Univ Washington, Dept Global Hlth, Ctr AIDS & Sexually Transmitted Dis, Seattle, WA 98195 USA
[3] Univ Limerick, Dept Math & Stat, Limerick, Ireland
[4] Univ Washington, Dept Stat, Seattle, WA 98195 USA
[5] Univ Washington, Harborview Med Ctr, Seattle, WA 98104 USA
[6] Univ Washington, Dept Biostat, Seattle, WA 98195 USA
[7] Univ Washington, Dept Med, Div Allergy & Infect Dis, Seattle, WA USA
[8] Batelle Ctr Publ Hlth Res & Evaluat, Seattle, WA USA
[9] Ctr Dis Control & Prevent, Div Sexually Transmitted Dis Prevent, Ctr Human Immunodeficiency Virus Sexually Transmi, Atlanta, GA USA