[1] UCL, Ctr Behav Med, London WC1E 6BT, England
[2] Cent & NW London NHS Fdn Trust, London, England
[3] Brighton & Sussex Univ Hosp NHS Trust, Brighton, E Sussex, England
[4] Homerton Univ Hosp NHS Fdn Trust, Ctr Study Sexual Hlth & HIV, London, England
[5] Chelsea & Westminster Hosp NHS Fdn Trust, London, England
[6] Imperial Coll London, London, England
[7] Imperial Coll Sch Med St Marys, London, England
[8] Cardiff Univ, Sch Med, Cardiff, S Glam, Wales
[9] Univ Liverpool, Inst Infect & Global Hlth, Liverpool L69 3BX, Merseyside, England
[10] UCL, Dept Practice & Policy, London WC1E 6BT, England
[11] Royal Free London NHS Fdn Trust, HIV AIDS Serv, London, England
[12] Univ Edinburgh, Edinburgh EH8 9YL, Midlothian, Scotland
[13] Western Gen Hosp, Edinburgh EH4 2XU, Midlothian, Scotland
[14] Barts Hlth NHS Trust, London, England
[15] MRC, Clin Trials Unit, London, England
[16] Kings Coll London, London, England
[17] Kings Coll Hosp NHS Fdn Trust, London, England
[18] Imperial Coll Healthcare NHS Trust, London, England