Imperial College London


Faculty of MedicineSchool of Public Health

Honorary Lecturer



+44 (0)20 7594 3820m.pickles




UG5Praed StreetSt Mary's Campus






I work on modelling the HIV epidemic in different settings and amongst different risk populations. My main interest is in interventions which can be used to control or eliminate HIV, both biomedical interventions such as treatment-as-prevention and behavioural interventions such as community mobilization, and factors which can alter their effectiveness.

I have been responsible for the impact evaluation of the Avahan India AIDS Initiative established by the Bill & Melinda Gates Foundation. This is a large-scale targeted HIV intervention promoting condom use and providing STI services as well as structural intervention and community mobilization to around 300,000 highest-risk individuals including female sex workers and men who have sex with men. Using a combination of data and mathematical modelling I determined whether Avahan had any effect on the HIV intervention there, and estimated the infections averted, and future trends in the HIV epidemic in conjunction with Marie-Claude Boily at Imperial and Peter Vickerman at LSHTM. Results from this model were also used to produce cost-effectiveness estimates for Avahan in combination with economists at LSHTM.

I have also worked modelling HIV in Tanzania to help in designing a large-scale HIV trial, and the effect of violence, community empowerment and work environment for female sex workers on increasing their risk of HIV infection.

At present I work with Christophe Fraser and Anne Cori to develop a large-scale individual-based model of HIV transmission for the HPTN-071 PopART trial in Zambia and South Africa.

In my previous job I helped set up the African Insitute for Mathematical Sciences in South Africa.




Thomas R, Burger R, Harper A, et al., 2017, Differences in health-related quality of life between HIV-positive and HIV-negative people in Zambia and South Africa: a cross-sectional baseline survey of the HPTN 071 (PopART) trial, Lancet Global Health, Vol:5, ISSN:2214-109X, Pages:E1133-E1141

Ratmann O, Hodcroft EB, Pickles M, et al., 2017, Phylogenetic Tools for Generalized HIV-1 Epidemics: Findings from the PANGEA-HIV Methods Comparison, Molecular Biology and Evolution, Vol:34, ISSN:0737-4038, Pages:185-203

Heffernan A, Barber E, Thomas R, et al., 2016, Impact and Cost-Effectiveness of Point-Of-Care CD4 Testing on the HIV Epidemic in South Africa, Plos One, Vol:11, ISSN:1932-6203

Dureau J, Kalogeropoulos K, Vickerman P, et al., 2016, A Bayesian approach to estimate changes in condom use from limited human immunodeficiency virus prevalence data, Journal of the Royal Statistical Society Series C-applied Statistics, Vol:65, ISSN:0035-9254, Pages:237-257

Ramachandran S, Mishra S, Condie N, et al., 2016, How do HIV-negative individuals in sub-Saharan Africa change their sexual risk behaviour upon learning their serostatus? A systematic review, Sexually Transmitted Infections, Vol:92, ISSN:1368-4973, Pages:571-578

More Publications