Professor Hart's research interests include sexual riskbehaviour and the prevention of HIV and STIs, combining structural, behavioural,and biomedical approaches to prevention and the opportunities afforded by newprevention technologies. He has worked with a wide range of populations at riskof HIV and STIs, nationally and internationally. This includes men who have sexwith men, young people, sex workers, and vulnerable groups in developed anddeveloping countries.

His major contributions are to health policy and promotion, particularly in HIVand sexual health. Two significant examples are: needle exchange for injectingdrug users (IDU); HIV prevention in men who have sex with men (MSM).

After needs assessment which found high levels of sharingof drug injecting equipment amongst IDU he was instrumental in setting up, andthen evaluating, the first dedicated needle-exchange in the UK and the roll-outof this harm reduction strategy in England and Wales using combined behaviouraland biomarker data. This work has been cited internationally, helped with theadoption of harm minimisation globally, and contributed to reduced parenteraltransmission of HIV throughout the world.

His research on men who have sex with men is widely citedand has informed HIV prevention strategies in the UK and internationally. Heundertook the first community-based survey of prevalent HIV using oral fluidantibody tests and the first UK evaluation of peer-education for risk reductionin MSM. He led work which first described in Scotland increased risk-behaviourafter the introduction of HIV therapy in the mid-1990s, and subsequentlyspecified the undiagnosed fraction of HIV in community-recruited MSM across theUK. This work also demonstrated high levels of sexual risk taking in HIVpositive men. These studies have informed the development of HIV prevention inMSM in the UK and internationally and been vital for government and NGOprevention efforts.