[1] UCL, Populat Policy & Practice Programme, London NW3 2PF, England
[2] UCL, Res Dept Infect & Populat Hlth, HIV Epidemiol & Biostat Grp, London NW3 2PF, England
[3] Univ Southampton, Southampton Gen Hosp, Fac Med, Human Dev & Hlth, Southampton, Hants, England
[4] Homerton Univ Hosp NHS Fdn Trust, London, England
[5] Univ London Imperial Coll Sci Technol & Med, Sect Retrovirol & GU Med, London, England
[6] Univ KwaZulu Natal, Africa Ctr Hlth & Populat Studies, Mtubatuba, South Africa