Policy changes in opioid agonist therapy and impacts on HIV and hepatitis C prevention in Canadian federal prisons

The Canadian federal prison system has implemented a successful prevention-first model for people who use drugs, including all available opioid agonist therapies (OAT), prison needle and syringe programs, and treatment-as-prevention for HIV and hepatitis C virus (HCV). These strategies have contributed to sustained low prevalence of HIV (0.7%) and chronic HCV (3.6%).¹ This model has been viewed as a global benchmark for integrated HIV and HCV prevention and treatment in carceral settings.

Opioid use disorder (OUD) is common among carceral populations, and OAT is the most effective treatment for OUD. OAT reduces injection of opioids, overdose, mortality, HIV and HCV transmission, and crime, but its effectiveness depends on sustained retention.² Nearly half of people entering federal prisons were prescribed OAT in the 30 days before incarceration, and almost 25% of the approximately 14,000 incarcerated individuals receive OAT during imprisonment.^3,4 In 2024, 60%, 22%, and 18% of people treated with OAT were prescribed sublingual buprenorphine/naloxone (SL-BUP), methadone, and long-acting injectable buprenorphine (LAI-BUP), respectively.⁴ Patient autonomy has been a longstanding and integral part of Canada's federal prisons' successful OAT programme.

Against this backdrop, a recent policy change in the Canadian federal prison system risks reversing decades of progress in OUD treatment and HIV and HCV prevention. Effective October 1, 2025, LAI-BUP was designated as first-line therapy for OUD, with methadone available only under restricted circumstances (i.e., pregnancy or allergy). This shift has reduced patient choice for almost 2000 individuals once receiving SL-BUP and has altered a system previously grounded in low-threshold, patient-centred care.⁴ Evidence from behavioural and clinical research shows that adherence improves when treatment aligns with patient preferences and values, particularly for chronic conditions requiring sustained engagement.⁵ Such policy changes, particularly when not aligned with established clinical guidance, may rapidly destabilise treatment engagement and population-level prevention gains.

First, emerging evidence suggests substantially lower retention on LAI-BUP formulations compared with SL-BUP options. While LAI-BUP is designed to overcome barriers to daily medication adherence through reduced administrative frequency, real-world retention on LAI-BUP is approximately half that of SL-BUP at 90 days and declines substantially to ∼10% by 6–12 months.⁶ Patient preferences, suboptimal efficacy and patient comfort, evidenced by both supplemental SL-BUP to manage cravings or withdrawal and transition to SL-BUP, may explain discontinuation. This policy change may have rapid unintended consequences with OAT coverage, a quality indicator for HIV and HCV prevention, having already decreased by 15% from July to December 2025.⁴

Second, treatment retention on LAI-BUP will likely be disrupted following release from prison. Disruptions in continuity of care during the transition from custody to community are well-established drivers of overdose, mortality, and infectious disease transmission.⁷ Evidence suggesting improved retention on LAI-BUP vs. SL-BUP in the post-release period must be interpreted with caution: SL-BUP was variably dosed, follow-up periods were too short to be conclusive, and markedly different levels of post-release support, some exceeding real-world re-entry environments, were provided across treatment groups.^8,9 While LAI-BUP was listed on Canadian provincial/territorial formularies in February 2020, LAI-BUP remains the least prescribed OAT in the community, likely reflecting restricted public drug coverage in some jurisdictions, requirements for clinician certification, and patient preferences.¹⁰ This mismatch –where LAI-BUP is more easily accessed in federal prison than surrounding communities– will result in reduced retention, unravelling OAT benefits for thousands of people. Consequences may include increased overdose risk, drug-related mortality, injection-related infections, HIV and HCV transmission, and re-incarceration, each with substantial health system costs.²

Third, reducing OAT diversion is frequently cited as a rationale for prioritising LAI-BUP, yet there is limited evidence documenting the scale or impact of diversion in prison settings. Instead, diversion reflects unmet treatment needs, and policies that restrict access to preferred therapies risk reshaping risk environments in ways that undermine engagement, continuity of care, and prevention of HIV and HCV.

Taken together, this policy change will weaken patient autonomy and trust, reduce retention on OAT, and erode the highly effective strategies that have sustained low prevalence of HIV and HCV in Canadian federal prisons. A system previously regarded as a model for public health innovation now faces potential erosion of its core strengths. These risks are avoidable if policy adjustments preserve treatment flexibility and patient-centred care. Without such adjustments, gains in HIV and HCV prevention may be reversed, with increases in overdose, mortality, and HIV and HCV transmission in a highly vulnerable population who would otherwise be able to choose the treatment most aligned with their values if they were in the community.

Contributors

NK, LMM, and FLA conceptualized the comment, NK wrote the original draft, and LMM, MS, OP, and FLA contributed to reviewing and editing the manuscript.

Declaration of interests

None.