From 1986 to 1999 the Centre for Sexual Health & HIV Research housed the MRC UK Centre for Co-ordinating Epidemiological Studies of HIV and AIDS, which formed the basis for establishing the Epidemiology and Social Science Research Group. This Group of around 20 staff, headed by Dr Pam Sonnenberg, conducts research into the epidemiological, social and behavioural aspects of HIV infection and other STDs. The Epidemiology and Social Science Research Group is increasingly involved in randomised controlled trials of behavioural interventions and evaluations of local and National Health Service interventions and strategies. Collaborations with researchers in other institutions including the London School of Hygiene and Tropical Medicine (LSHTM), the Institute of Education and MRC Units in London and Glasgow have resulted in a number of successful projects. These include the SHARP study of HIV positive gay men and the impact of ART on sexual behaviour, comparisons of the sexual behaviour of gay men in London, Brighton, Manchester, Edinburgh and Glasgow, and analyses of data sets from two large randomised controlled trials of sex education in schools. Within the department of PCPS, there is also joint working with the Centre for Infectious Disease Epidemiology on the Medical School’s Hampstead Campus (Anne Johnson) and with epidemiologists in the Royal Free Centre for HIV Medicine (Andrew Phillips), particularly on the National survey of sexual attitudes and lifestyles (Natsal); studies of STIs in Primary Care. The Group's international work has included research into the emerging HIV epidemic in Eastern Europe, which is largely driven by injecting drug use and intervention development work with vulnerable populations in different regions of India (Goa and Gujarat). Members of the group are also involved in large projects on peer-led sex education, and clinical trials of acyclovir prophylaxis, to reduce HIV incidence in Zimbabwe. These studies are being carried out in collaboration with the University of Zimbabwe, LSHTM and the University of California in San Francisco (UCSF), with one member of the group, Frances Cowan, being based in Harare.