[1] Univ North Carolina Chapel Hill, Inst Global Hlth & Infect Dis, Chapel Hill, NC 27599 USA
[2] London Sch Hyg & Trop Med, Fac Infect & Trop Dis, Clin Res Dept, London, England
[3] Univ Melbourne, Melbourne Sch Populat & Global Hlth, Fac Med Dent & Hlth Sci, Melbourne, Vic, Australia
[4] Nigerian Inst Med Res, Clin Res Dept, Lagos, Nigeria
[5] Glasgow Caledonian Univ, Sch Hlth & Life Sci, Glasgow, Lanark, Scotland
[6] NHS Greater Glasgow & Clyde, Sandyford Sexual Hlth Serv, Glasgow, Lanark, Scotland