Imperial College London


Faculty of MedicineSchool of Public Health

Research Associate or Fellow







Praed 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.

My current work involves using modelling combined with data from Zimbabwe to understand to what extent different barriers prevent individual from accessing and using HIV prevention tools such as pre-exposure prophylaxis. Previously, I developed a computationally efficient individual-based model of HIV transmission that was used in analysis of results of the HPTN-071 (PopART) trial, a community-based HIV combination prevention trial in Zambia and South Africa. I was also responsible for the impact evaluation of the Avahan India AIDS Initiative established by the Bill & Melinda Gates Foundation, 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. I have also worked modelling the effect of violence, community empowerment and work environment for female sex workers on increasing their risk of HIV infection. 

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



Lazarus L, Herpai N, Pavlova D, et al., 2022, Exploring the impact of military conflict on sex work in Ukraine: Women's experiences of economic burden, Global Public Health, ISSN:1744-1692

Pickles M, Cori A, Probert WJM, et al., 2021, PopART-IBM, a highly efficient stochastic individual-based simulation model of generalised HIV epidemics developed in the context of the HPTN 071 (PopART) trial., Plos Comput Biol, Vol:17

Herpai N, Lazarus L, Forget E, et al., 2021, Exploring the dynamics of workplace typologies for sex workers in Eastern Ukraine, Global Public Health, ISSN:1744-1692

Thomas R, Probert W, Sauter R, et al., 2021, Cost and cost-effectiveness of a universal HIV testing and treatment intervention in Zambia and South Africa: evidence and projections from the HPTN 071 (PopART) trial, The Lancet Global Health, Vol:9, ISSN:2214-109X, Pages:e668-e680


Davis K, Muzariri K, Mangenah C, et al., Modelling the interaction between depression and HIV incidence in Manicaland, East Zimbabwe, Fast Track Cities 2021

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