My research focuses on examining how social and health policies and interventions influence people who sell sex and/or inject drugs’ vulnerability to blood-borne viruses, sexually transmitted infections (STI) and other health harms. Much of this work has focused on the UK, Russian Federation, East Africa and India and currently in Myanmar, Afghanistan and Colombia.

My research has used different quantitative techniques, including: capature recapture to estimate the size of hidden populations; systematic reviews and meta analyses to synthesise evidence on HIV/HCV co-infection, the effect of migration on STIs/HIV among sex workers, the effectiveness of brief interventions on alcohol; cross-sectional studies to measure prevalence of HIV/HCV and STIs and associated risk factors among people who inject drugs and sex workers. Although primarily an epidemiologist, much of my research is mixed-methods, incorporating qualitative methods to ‘ground’ structured indicators and understand the complex social processes that drive individuals’ behaviour as well as collaborating closely with mathematic modellers to simulate intervention impact on disease transmission.  I conducted a mixed method review of social science and epidemiological evidence to assess the magnitude and pathways through which criminalisation affects sex workers' safety and health.  I have conducted collaborative projects to measure the effectiveness and cost-effectiveness of needle/syringe programmes and opiate substitution therapy on hepatitis C incidence among people who inject drugs and  provided technical support on a cluster randomised controlled trial that seeks to measure the effect of a multi-level intervention to reduce intimate partner violence towards sex workers in Karnataka, India.

My methodological interests lie in how best to combine qualitative and quantitative methods to measure the causal pathways through which structural factors (i.e. social policies) increase risk behaviours and vulnerability to infectious disease and other health harms among vulnerable and marginalised populations.

I am currently leading two participative mixed-method studies funded by the National institute for Health Research. Both studies are community-academic partnerships. The East London Project is a collaboration with sex worker specialist serices 'Open Doors' and 'National Ugly Mugs' as well as the Homerton Hospital, University of Bristol and Imperial College . It aims to evaluate how removing sex work-related police enforcement could affect sex workers’ safety, sexual and emotional health (e.g. risk of HIV, STIs, depression and anxiety) and access to health and social care services, in East London. http://eastlondonproject.lshtm.ac.uk

The Homeless Health Peer Advocacy evaluation is a collaboration with Kings College London, UCL and Groundswell a third sector organisation that train peer advocactes to accompany people currently homeless to health services, supporting them navigate the process and overcome barriers. The research will evaluate peer advocacy among people experiencing homelessness in London in terms of impact, cost-effectiveness and process.  I am co-investigator on a grant 'Drugs and (dis) Order' led by SOAS that seeks to explore the role of illegal economies and drug production in countries transitioning from conflict to peace time.  My role is to measure the health effects of drug use in the context of drug production, internal displacement and ethnic conflict.