1. Modeling the potential impact of providing ART and OAT in prison and upon release on HIV incidence among PWID in Tijuana, Mexico
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Annick Bórquez, Daniela Abramovitz, Leo Beletsky, Steffanie A. Strathdee, Peter Vickerman, MC Boily, Natasha K Martin
Division of Global Public Health,
University of California San Diego
Lisbon Addictions, 10/25/2017

2. Conflict of interest
None to declare

3. Incarceration as an opportunity to reach PWID with health services
Incarceration has been consistently associated with increased risk of bloodbourne infections among PWID1-2
Right to health in prison is an international norm
WHO/UNODC recommend comprehensive package of HIV prevention, care, and support for incarcerated people2
Prisons as opportune settings to:
Reach PWID with health services since low access in the community3
Start opioid agonist therapy (OAT) and antiretroviral treatment (ART), as treatment can be directly observed and monitored2-3
Quantifying the potential impact of implementing HIV and OAT interventions in prison is important to inform policy making and advocate for change
Dolan K, Wirtz AL, Moazen B, et al. Global burden of HIV, viral hepatitis, and tuberculosis in prisoners 18 and detainees. Lancet 2016
Csete J. et al. Public health and international drug policy, The Lancet Commissions, 2016; 387: 1427–80
Beyrer C, et al. Prisoners, prisons, and HIV: time for reform. The Lancet, July
Risks inside prison as less to no access to sterile syringes/condoms
Risks upon release as a result of hardship (homelessness, unemployment) and regaining access to drugs

4. Tijuana, as case study Large PWID population (5,000-10,000)
“Proyecto El Cuete IV”: cohort study following 734 PWID in Tijuana bi- annually from
HIV test
self-reports of sexual and drug- using behaviors, policing, incarceration, and access to HIV and harm reduction services
Among PWID, HIV prevalence is 3.5%, HIV incidence is 1-2%/year
Access to HIV and harm reduction services is very low (<3% receiving ART or OAT)

5. Prison as a setting to reach PWID in Tijuana
85% and 59% of male and female PWID have ever been incarcerated
Mean number of 5 (SD: 4.6) and 3 (SD: 2.7) incarcerations since starting injecting for male and female PWID, respectively
Average sentence length: 4 months

6. Aims Use mathematical modeling to:
1) Estimate the potential impact of providing ART or/and OAT in prisons and upon release on HIV incidence among PWID in Tijuana
2) Assess the impact of also scaling up ART and OAT among PWID in the community
Graph to justify aim 2: more likely to implement these services I the community than in prison according to experiences from countries which have done either or both so exploring this scenario too (even if the main aim of this study is to explore the use of prisons as settings to link PWID to health services
Source: Csete J. et al. The Lancet Commissions, 2016

7. Methods
Dynamic, deterministic compartmental model of HIV transmission among PWID
Injecting and sexual transmission
Disaggregated by sex, incarceration stage, OAT and HIV stage including ART
Varied parameters associated with demography, incarceration patterns and HIV transmission
Fitted to data on HIV prevalence and incidence using Latin Hypercube Sampling and resampled best fitting simulations

8. Intervention scenarios
ART
OAT
Prison and release
Community
Scenario 1
Scenario 2
Scenario 3
Scenario 4
Coverage of ART/OAT in the “community scenario” varies because I use a rate and it translates into different coverages depending on the epidemic projection. These are not the exact min and max, will provide these.

9. Intervention characteristics
ART
OAT
Prison
Community
Efficacy
30%-75% reduction in sexual and injecting transmission
54%(33%-68%) reduction in acquisition through injecting
Drop out rate
0/year
0.2/year
1/year
Coverage S-1
100%
declines 0%
Coverage S-2
Coverage S-3
Coverage S-4
45-55%
20%-30%

10. Model diagram: Scenario 1 Scenario 2 Scenario 3 Scenario 4 Never
Incarcerated
Recently
Incarcerated
Not Recently
Incarcerated
Prison
Off OAT
On OAT
Off ART
On ART

11. Proportion of new HIV infections averted among PWID in Tijuana from 2018 to 2030 through providing ART or/and OAT in prison and upon release.
Mean: 45.8%
Mean: 30.1%
Mean: 20.2%
Mean: 18.5%

12. Conclusions
Prisons could provide a valuable opportunity for initiating PWID on to HIV and drug treatment in Tijuana
Nearly a third of new HIV infections could be averted between through the provision of ART and OAT in prison, conditional on linkage upon release.
Substantial (although still suboptimal) scale up of ART and OAT in the community would further curb the epidemic by preventing nearly 50% of new HIV infections

13. Limitations and future work
Self reported behaviors
Model’s capacity to reproduce epidemic dynamics
Future work should examine:
Explore feasibility of implementing these services in prisons in Tijuana through qualitative interviews with previously incarcerated PWID, health care providers in prison and decision makers.
Explore synergies between OAT and ART adherence and incarceration rates
Evaluate cost-effectiveness
Bayesian
sensitivity

14. Acknowledgments Thank you! Funding:
-NIDA U.S.-Mexico drug abuse prevention research fellowship
-UC-MEXUS CONACyT postdoctoral fellowship
-UC San Diego Center for AIDS Research (NIAID P30 AI36214)
-NIDA grant R01 DA
-NIDA grant R01 DA A1
Patty González Zúñiga
Kenya Lazos
All the participants of El Cuete study
Thank you!
Pictures from “Tomorrow is a long time: Tijuana’s unchecked
HIV/AIDS epidemic” by John Cohen and Malcom Linton

15. Extra slides

17. Model fitting:

18. Modeling Analysis: Never incarcerated Prison
Baseline
Never incarcerated
Prison
Recently incarcerated (< 6 months ago)
Previously Incarcerated (> 6months ago)
Number of new HIV infections
Reproduce observed trends
Simplified cohort model used to estimate:
-Proportion ever incarcerated when starting injecting
-Primary incarceration rate
RR HIV
RR HIV