[1] Northamptonshire Integrated Sexual Hlth & HIV Ser, Northampton, England
[2] Univ Calif San Diego, La Jolla, CA 92093 USA
[3] Barts Hlth NHS Trust, London, England
[4] London North West Univ Healthcare NHS Trust, London, England
[5] Natl STD AIDS Control Programme Sri Lanka, Colombo, Sri Lanka