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Estimating the potential impact and efficiency of PrEP for FSWs and MSM in Bangalore, southern India. K.M. Mitchell 1 , H.J. Prudden 1 , B.M. Ramesh 2.3 , R. Washington 2,4 , S. Isac 2 , S. Rajaram 5 , F. Terris-Prestholt 1 , C.H. Watts 1 , P. Vickerman 1,6
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Estimating the potential impact and efficiency of PrEP for FSWs and MSM in Bangalore, southern India K.M. Mitchell1, H.J. Prudden1, B.M. Ramesh2.3, R. Washington2,4, S. Isac2, S. Rajaram5, F. Terris-Prestholt1, C.H. Watts1, P. Vickerman1,6 1London School of Hygiene and Tropical Medicine, London, UK, 2Karnataka Health Promotion Trust, Bangalore, India, , 3University of Manitoba, Winnipeg, Canada, 4St John's Research Institute, Bangalore, India, 5CHARME-India Project, Bangalore, India, 6University of Bristol, Bristol, UK Improving health worldwide www.lshtm.ac.uk
Bangalore: background • In Bangalore, HIV infection is concentrated amongst • female sex workers (FSWs) HIV prevalence 8.0% (2009) • FSWs’ commercial clients 2.4% (2007) • men who have sex with men (MSM) 16.5% (2009) • Low general population HIV prevalence (ANC 0.4%, 2009) • Following previous interventions, reported condom use by MSM and FSW is high (75-90% always use condoms with high-risk partners) • Not all acts or partnerships are covered by condoms
Pre-exposure prophylaxis (PrEP) • Given to HIV negative individuals at high risk of HIV infection • Daily oral tablet containing antiretroviral drugs • MSM: iPrex trial showed 44% reduction in HIV incidence (Grant et al 2010 NEJM) • Heterosexuals: Trials show 0-75% reduction in HIV incidence (Baeten et al 2012 NEJM, Thigpen et al 2012 NEJM, Van Damme et al 2012 NEJM, Amico et al 2014 CID) • Trial efficacy strongly related to drug adherence (Amico et al 2014 CID) • FSW: trials & demonstration projects planned or in progress
What could be the additional impact of providing PrEP for FSW and/or MSM in this setting?
Methods: mathematical modelling • Mathematical models widely used to estimate the impact of different HIV interventions and inform policy • Deterministic model which describes HIV transmission between MSM, FSW, clients and low-risk members of the general population • Model inputs: • Behavioural data from Bangalore on sexual partners, frequency of sex acts, condom use, rates of HIV testing, linkage to ART, rates of dropout from ART • Biological data from the literature on the probability of infection per sex act, condom and ART efficacy, HIV progression rates and death rates on and off ART
Methods: model fitting • Model was fitted to data from Bangalore: • HIV prevalence for MSM, FSW and clients • Overall ART coverage data • Model inputs were randomly sampled many times • Only combinations which gave outputs agreeing with the data were retained for further analysis
Methods: modelled interventions • Model used to estimate the impact of PrEP – number of infections averted over 10 years • PrEP intervention starting in January 2014 • 20% annual dropout from PrEP intervention • PrEP intervention characteristics: • Targeted to FSW, high-risk (HR-) MSM or both • Effectiveness (efficacy*adherence) 30% or 60% • Coverage after 5 years: 20%, 40% or 60% of target group
Results: targeting FSWs, impact among FSWs • 40% coverage of FSWs and 60% PrEP effectiveness → ~23% of FSW infections averted • Higher impact at higher coverage and/or effectiveness • Similar results for MSM
Results: impact in whole population • 40% coverage of FSWs and 60% PrEP effectiveness → 3.4% of infections averted overall • Targeting MSM at same coverage has lower population-level impact • Targeting both groups – impact almost additive • Impact increases over time
Results: HIV infections averted by subgroup • More infections averted in general population when FSW targeted
How efficient is providing PrEP for FSW and/or MSM in this setting? Efficiency = person-years of PrEP per life-year gained
Results: PrEP efficiency in whole population • 40% coverage and 60% PrEP effectiveness: PrEP most efficient when targeting FSWs only or FSW+MSM • Efficiency improves over time
Conclusions • What could be the additional impact of providing PrEP for FSW and/or MSM in this setting? • Substantial reduction in incidence amongst target group • Smaller reduction in incidence in the whole population • Larger impact from targeting FSW vs MSM • How efficient is providing PrEP for FSW and/or MSM in this setting? • More efficient to target FSW than MSM • More efficient in the longer term • Could higher efficiency be achieved if PrEP is targeted to those unable to use condoms consistently?
Acknowledgements • This work was supported by the Bill and Melinda Gates Foundation* *The *views expressed herein are those of the authors and do not necessarily reflect the official policy or position of the Bill & Melinda Gates Foundation. London School of Hygiene & Tropical Medicine • Fern Terris-Prestholt • Holly Prudden • Anna Foss • Charlotte Watts University of Bristol • Peter Vickerman Karnataka Health Promotion Trust • BM Ramesh • Reynold Washington • ShajyIsac CHARME India Project • S Rajaram