1. Incarceration and People Who Inject Drugs in Ukraine: Modelling its Role in HIV Transmission and the Impact of Introducing OST in Prisons
Jack Stone, Ellen Brooks-Pollock, Frederick Altice, Lyuba Azbel, Pasha Smyrnov, Natasha Martin, Peter Vickerman

2. Conflict of Interest Disclosure
I have no conflict of interest to declare.

4. Background & Introduction

5. PWID Experience High Incarceration Rates
Opportunity to engage an otherwise difficult to reach population
Russia: Grau AIDS Behav. 2011; Ukraine: AIDS Alliance IBBA 2013;
Australia: Topp J. Urban Health 2013; Scotland: Taylor Addiction 2013; Thailand: Hayashi BMC P.H.2013; England: Hope J.V.H. 2011

6. Limited Interventions in Prison
Only 8 countries report having Needle and syringe programmes (NSP) in prison1 compared to 82 in the community2
Concerns that prison NSPs will encourage injecting drug use, and needles will be used as weapons seem to be unfounded3
Opiate substitution therapy (OST) is available in prisons1 in nearly 40 countries compared to 72 in the community4
But, prison OST coverage is often low and often not available in all prisons within a country
Neither OST or NSP is available in Ukrainian prisons.
[1] Kamarulzaman Lancet 2016; [2] Mathers Lancet 2010;
[3] Stover Int. J. Drug Policy 2003; [4] Jurgens J. Int. AIDS Soc. 2011;

7. Incarceration and Injecting Risk
PWID inject less frequently in prisons than in the community 1
BUT injection equipment is scarce which leads to increased high-risk sharing1
History of incarceration frequently found to be a risk factor for HIV prevalent infection in the community
Recently released PWID frequently report increased risk behavior2-6
[1] Dolan Int. J. Drug Policy 2015; [2] Allen IJDP 2012;
[3] Capeda DAD 2015; [4] Milloy Drug and Alc Rev 2008;
[5] Wood Pub Health Reports 2005; [6] Milloy BMC PH 2009

8. Ukraine Case Study
Compared to never incarcerated PWID, previously incarcerated PWID:
Inject more frequently; 3.9 injections more per month (95%CI )1
Are more likely to share syringes in the last month (aOR=1.5, 95%CI ) 1
PWID released in the last 12 months are particularly likely to report syringe-sharing (aOR=2.2, 95%CI ) 1
[1] AIDS Alliance IBBA 2013; [2] Azbel J. Int. AIDS Soc. 2014

9. Ukraine Case Study
Figure: AIDS Alliance IBBA 2013

10. Methods

11. Model Structure

12. Model Parameterisation and Calibration
The model’s incarceration dynamics were calibrated first.
An incarceration dynamics sub-model was used to track a simulated closed cohort of 1000 PWID for 35 years from their onset of injecting.
An Approximate Bayesian computation sequential Monte Carlo scheme1 was used to obtain a sample of 1,000 incarceration-related parameter sets that fit the incarceration data sufficiently well.
13 month average time incarcerated.
[1] Toni J. R. Soc. Interface

13. Model Fits

14. Model Parameterisation and Calibration
The HIV transmission aspect of the model was calibrated to:
HIV prevalences among never and previously incarcerated PWID in 2013 (12.8% and 28%), and currently incarcerated PWID in 2011 (28.5%).
ART coverage amongst PWID in 2011 and 2015 (14.6% and 19.5%)
An Approximate Bayesian computation sequential Monte Carlo scheme was used to obtain a sample of 1,000 parameter sets.
The model assumed a stable epidemic in 2008, prior to the scale-up of ART.

15. Model Parameterisation and Calibration
An uninformative prior was used for the relative transmission risk amongst currently incarcerated PWID.
Relative transmission risk for previously incarcerated PWID estimated by combining self-reported data on the frequency of injecting and proportion recently reporting syringe sharing for each incarceration group
relative risk within 1-year post-release and subsequently
Uniform priors were used for the relative transmission risk among previously incarcerated PWID

16. Model projections We used the model to project the:
Contribution of incarceration to HIV transmission, by setting transmission risk during and post-prison to that of never incarcerated PWID.
Impact of preventing further incarceration of PWID.
Impact of introducing OST into prisons; both with and without retention following release.

17. results

18. Infections Averted Over 2015-2030

19. Impact Projections

20. Sensitivity Analysis
Posterior median and range of the relative transmission risk compared to never incarcerated PWID
% of HIV infections averted over 15 years for different intervention scenarios
Model prior scenario
Currently incarcerated PWID ( 𝜷 𝟏 )
PWID released in <12 months ( 𝜷 𝟐 )
Previously incarcerated PWID ( 𝜷 𝟑 )
No effect of incarceration on transmission risk (15 year PAF)
No further PWID incarceration
Scale-up of prison OST with retention after release
Scale-up of prison OST without retention after release
Baseline model
𝛽 1 >0
1.9≤𝛽 2 ≤3.3
1.4≤ 𝛽 3 ≤2.0
0.9
( )
2.6
( )
1.7
( )
55.1
( )
12.8
( )
19.8
( )
5.6
( )
Sens analysis 1
𝛽 3 >1
1.0
( )
N/A
1.6
( )
41.1
( )
-6.2
( )
15.0
( )
7.7
( )
Sens analysis 2
𝛽 3 >0
1.1
( )
1.5
( )
34.1
( )
-2.2
( )
15.8
( )
8.9
( )

21. Conclusions

22. Conclusions
Incarceration, and specifically increases in injecting risk post- incarceration, fuel the HIV epidemic in Ukraine’s PWID.
HIV prevention interventions should be strategically targeted to previously-incarcerated PWID.
OST expansion in prisons with effective transition upon release, could be an effective way of achieving this.
Strategies that reduce incarceration should also be considered.

23. Limitations
Our results and conclusions rely strongly on the assumption of elevated transmission risk among previously incarcerated PWID
Despite this, our conservative projections and sensitivity analyses suggest that incarceration could be an important driver of the HIV epidemic among PWID in Ukraine.
The model could not determine whether transmission risk differed between currently and never incarcerated PWID
Future studies should examine longitudinal changes in risk before, during and after incarceration

24. Acknowledgements Ellen Brooks-Pollock – University of Bristol
Frederick Altice – Yale University
Lyuba Azbel – London School of Hygiene and Tropical Medicine
Pasha Smyrnov – Ukrainian Institute for Public Health
Natasha Martin – University of California San Diego
Peter Vickerman – University of Bristol