Theme: Epidemiology & Public Health Research Year: 2022
Background: Given consistently strong associations between policing encounters/incarceration and
injection-related risk behaviors, a 3-hour police education program (“Proyecto Escudo” [Project Shield])
was conducted from February 2015 – May 2016 by the Tijuana Police Academy and Public Safety
Ministry to align policing with evidence-based public health principles. We evaluated the impact and
cost-effectiveness of “Escudo” on HIV and overdose among people who inject drugs (PWID).
Methods: Using log-binomial regression in a cohort of PWID in Tijuana, we assessed temporal trends in
any incarceration (past 6 months) in the periods before (March 2011 – March 2015), during (March
2015-March 2016), and after Escudo implementation (March 2016-November 2018). We developed a
dynamic model, which simulated HIV transmission and fatal overdose, calibrated to local HIV
prevalence, incidence, and incarceration. We assessed the cost-effectiveness of Escudo compared to a
counterfactual of no Escudo, assuming a 2-year intervention effect and 50-year time horizon. Costs
(2022 USD) were included for the intervention, antiretroviral therapy, and incarceration. Health
outcomes were tracked in disability-adjusted life years (DALYs). The mean incremental costeffectiveness ratio (ICER) was evaluated against a willingness-to-pay threshold of per capita GDP
Results: Recent incarceration declined by 68% in the post-Escudo period (RR 0.32, 95%CI: 0.26-0.40)
compared to pre-Escudo, consistent with police self-reports of reduced drug-related arrests over the
same period. Over the two-year period during Escudo follow-up 1.7% [95% uncertainty interval (I): 0.4-
2.4%] of new HIV cases and 9.8% [95%I: 3.3-21.4%] of fatal overdoses among PWID were averted. The
intervention costed USD$149/officer trained and was cost-effective (mean ICER $6,154/DALY averted),
assuming the decline in incarceration was attributed to it.
Conclusion: By reducing incarceration, Escudo was a cost-effective strategy that aligned human-rights
based policing and public health. It could serve as a model for settings where policing constitutes
structural HIV and overdose risk among PWID.
Disclosures: No pharmaceutical grants were received in the development of this study.