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The “ESCUDO” [SHIELD in Spanish] study was funded by the National Institutes of Drug Abuse (NIDA, R01DA039073). This was the first ever grant issued by NIDA to evaluate the health impacts of a law enforcement training.   


The ESCUDO study was spurred by the historic 2009 reform decriminalizing possession of small amounts of drugs in Mexico. These reforms were also intended to increase access to substance use treatment and reduce reliance on incarceration as a response to problematic drug use. Given the historical gap between the laws on the books and how they are implemented by police, the study was designed to evaluate a police education program designed to align officer practices with recent reforms. 

As part of the study, U.S.-based researchers from UC San Diego collaborated with the Tijuana Police Department to create and implement an evidence-based police education program -- “Proyecto ESCUDO,” or Project SHIELD. Using the SHIELD model as a foundation, Proyecto ESCUDO used evidence-based teaching techniques and curricula to reduce harmful police practices while supporting the health of people who inject drugs (PWID). 


Implemented from February 2015 to May 2016, Proyecto ESCUDO trained officers on occupational safety knowledge, drug decriminalization, needlestick injury (NSI) prevention, and the evidence-based benefits of harm reduction services for both the community and for law enforcement officers. Specifically, ESCUDO reframes service referrals (for example, to harm reduction and social support services) as task-shifting to reduce the occupational burnout and stress on law enforcement officers as they respond to the overdose crisis, often without adequate training or tools. The ESCUDO team also developed and delivered an NSI response and surveillance system for the department.

In total, the team trained over 1,800 police officers and followed up with nearly 800 of those trainees over two years. Evaluation found significant and sustained improvements in the knowledge, attitudes, and practices of Tijuana law enforcement officers and their interactions with PWID. Specifically, we found significant reductions in accidental needle stick risk (16.2% decrease) at 3 months, with a sustained decrease of 17.8% through 24 months. Knowledge on key issues pertaining to infectious disease, drug policies, and referral to treatment also showed sustained improvement.

The SHIELD model also helped to bolster community health. Among people who use drugs, the implementation of the police training was associated with a 21% lower odds of recent incarceration per three-month period, averted 2% of new HIV infections and 12% of fatal overdoses. It also impacted officer willingness to make service referrals, as a mode of task shifting. In this setting, SHIELD was cost-effective, demonstrating great promise as a model with dual benefits for occupational health of first responders and for community wellbeing.

Recent Work

We evaluated "Project ESCUDO", a police education program to prevent HIV and improve occupational safety among police that was implemented in Tijuana, Mexico from 2015-2016.  The goal of the analysis was to understand how modifying policing practices affected HIV and overdose among people who inject drugs.  We used data from a cohort of people who inject drugs in Tijuana and observed a significant decline in incarceration rate after police received the ESCUDO training.  We estimated that in the two years after ESCUDO was implemented, about 2% of new HIV cases and 12% of fatal overdoses could have been averted due to ESCUDO. We found this intervention to have good value for money compared to a scenario if ESCUDO had not been implemented. 


Evaluamos el "Proyecto ESCUDO", un programa de educación que fue implementado en Tijuana del 2015 al 2016 para promover la prevención del VIH y la seguridad ocupacional de la policía. El objetivo del análisis de costo-efectividad era cuantificar el impacto de la modificación de los comportamientos policiales con respecto a la transmisión de VIH y casos de sobredosis entre personas que se inyectan drogas.  Analizamos datos de un cohorte de personas que se inyectaron drogas en Tijuana y observamos una reducción significativa de la tasa de encarcelamiento después de que la policía recibió entrenamiento.  Estimamos que en los dos años posteriores a la implementación del Proyecto ESCUDO, aproximadamente el 2% de los nuevos casos de VIH y 12% de las sobredosis fatales podrían haber sido prevenidos gracias al Proyecto ESCUDO.  Concluimos que esta  intervención demostró una buena relación calidad-precio comparada con un escenario en el que el Proyecto ESCUDO no hubiera sido implementado.

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