Dataset Information

Is hepatitis C virus (HCV) elimination achievable among people who inject drugs in Tijuana, Mexico? A modeling analysis.

ABSTRACT:

Background

In 2019, Mexico became the first Latin American country committed to hepatitis C virus (HCV) elimination, but the amount of intervention scale-up required is unclear. In Tijuana, HCV among people who inject drugs (PWID) is high; yet there is minimal and intermittent harm reduction, and involuntary exposure to compulsory abstinence programs (CAP) occurs which is associated with increased HCV risk. We determined what combination intervention scale-up can achieve HCV elimination among current and former PWID in Tijuana.

Methods

We constructed a dynamic, deterministic model of HCV transmission, disease progression, and harm reduction among current and former PWID parameterized to Tijuana (~10,000 current PWID, 90% HCV seropositive, minimal opiate agonist therapy [OAT] or high coverage needle/syringe programs [HCNSP]). We evaluated the number of direct-acting antiviral (DAA) treatments needed from 2019 to achieve elimination targets (80% incidence reduction, 65% mortality reduction by 2030) with: (a) DAAs alone, (b) DAAs plus scale-up of OAT+HCNSP (up to 50% coverage of OAT and HCNSP separately, producing 25% of PWID receiving both), (c) DAAs plus CAP scale-up to 50%. Scenarios examined the number of DAAs required if prioritized to current PWID or provided regardless of current injection status, and impact of harm reduction interruptions.

Results

Modeling suggests among ~30,000 current and former PWID in Tijuana, 16,160 (95%CI: 12,770-21,610) have chronic HCV. DAA scale-up can achieve the incidence target, requiring 770 treatments/year (95%CI: 640-970) if prioritized to current PWID. 40% fewer DAAs are required with OAT+HCNSP scale-up to 50% among PWID, whereas more are required with involuntary CAP scale-up. Both targets can only be achieved through treating both current and former PWID (1,710 treatments/year), and impact is reduced with harm reduction interruptions.

Conclusions

Elimination targets are achievable in Tijuana through scale-up of harm reduction and DAA therapy, whereas involuntary CAP and harm reduction interruptions hamper elimination.

SUBMITTER: Marquez LK

PROVIDER: S-EPMC8133359 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Background and aimsIn Latin America, Mexico was first to launch a hepatitis C virus (HCV) elimination strategy, where people who inject drugs (PWID) are a main risk group for transmission. In Tijuana, HCV seroprevalence among PWID is > 90%, with minimal harm reduction (HR). We evaluated cost-effectiveness of strategies to achieve the incidence elimination target among PWID in Tijuana.MethodsModeling study using a dynamic, cost-effectiveness model of HCV transmission and progression among active and former PWID in Tijuana, to assess the cost-effectiveness of incidence elimination strategies from a health-care provider perspective. The model incorporated PWID transitions between HR stages (no HR, only opioid agonist therapy, only high coverage needle-syringe programs, both). Four strategies that could achieve the incidence target (80% reduction by 2030) were compared with the status quo (no intervention). The strategies incorporated the number of direct-acting anti-viral (DAA) treatments required with: (1) no HR scale-up, (2) HR scale-up from 2019 to 20% coverage among PWID, (3) HR to 40% coverage and (4) HR to 50% coverage. Costs (2019 US$) and health outcomes [disability-adjusted life years (DALYs)] were discounted 3% per year. Mean incremental cost-effectiveness ratios (ICER, $/DALY averted) were compared with one-time per capita gross domestic product (GDP) ($9698 in 2019) and purchasing power parity-adjusted per capita GDP ($4842-13 557) willingness-to-pay (WTP) thresholds.ResultsDAAs alone were the least costly elimination strategy [$173 million, 95% confidence interval (CI) = 126-238 million], but accrued fewer health benefits compared with strategies with HR. DAAs + 50% HR coverage among PWID averted the most DALYs but cost $265 million, 95% CI = 210-335 million). The optimal strategy was DAAs + 50% HR (ICER $6743/DALY averted compared to DAAs only) under the one-time per-capita GDP WTP ($9698).ConclusionsA combination of high-coverage harm reduction and hepatitis C virus treatment is the optimal cost-effective strategy to achieve the HCV incidence elimination goal in Mexico.

Project description:ImportanceThe success of direct-acting antiviral therapies for chronic hepatitis C virus (HCV) infection led the World Health Organization to set elimination targets by 2030. For the United States to achieve these benchmarks, public health responses must target high-risk populations, such as people who inject drugs (PWID), a group with high rates of HCV incidence and low rates of treatment uptake.ObjectiveTo evaluate potential improvements in the HCV care cascade among PWID, focusing on improved testing, treatment uptake, and access to harm reduction.Design, setting, and participantsThis decision analytic model used a differential equation-based dynamic transmission model based on data from New Hampshire, an illustrative state with a large number of PWID and limited HCV treatment infrastructure. Surveillance data through 2020 was used for model parameterization, and the final analysis was conducted in May 2021.Main outcomes and measuresModel forecasts of chronic HCV cases and advanced-stage HCV outcomes from 2022 to 2045.ResultsA total of 6 scenarios were tested: (1) the base case, (2) improved harm reduction, (3) improved testing, (4) improved treatment, (5) improved testing and treatment, and (6) improved testing, treatment, and harm reduction. All scenarios with improved testing, treatment uptake, and/or access to harm reduction were associated with decreases in forecasted HCV prevalence and HCV-associated mortality compared with the base case. Improving harm reduction, testing, and treatment individually were forecast to reduce prevalence of HCV in 2045 from 69.7% in the base case to 62.8%, 45.7%, and 35.5%, respectively. Combining treatment and testing improvements was associated with a 2045 prevalence of 0.3%; adding harm reduction improvements was associated with further reductions in prevalence forecasts (to 0.2%), with fewer total treatments (10 960 vs 13 219 from 2022-2045).Conclusions and relevanceIn this modeling study, no single intervention was projected to achieve World Health Organization HCV elimination targets. Scenarios with improvements in both testing and treatment were associated with a prevalence of less than 3% by 2030 and achieved elimination targets. Adding improvements in harm reduction was associated with faster reductions in prevalence and fewer treatments.

Project description:BACKGROUND:Elimination of hepatitis C virus (HCV) among people who inject drugs (PWID) is a costly investment, so strategies should not only focus on eliminating the disease, but also on preventing disease resurgence. The aims of this study are to compute the minimum necessary antiviral therapies to achieve elimination with and without the additional expansion of harm reduction (HR) programs and to examine the sustainability of HCV elimination after 2030 if treatment is discontinued. METHOD:We considered two types of epidemic (with low (30%) and high (50%) proportion of PWID who engage in sharing equipment (sharers)) within three baseline chronic HCV (CHC) prevalence settings (30%, 45% and 60%), assuming a baseline HR coverage of 40%. We define sustainable elimination strategies, those that could maintain eliminations results for a decade (2031-2040), in the absence of additional treatment. RESULTS:The model shows that the optimum elimination strategy is dependent on risk sharing behavior of the examined population. The necessary annual treatment coverage to achieve HCV elimination under 45% baseline CHC prevalence, without the simultaneous expansion of HR programs, ranges between 4.7-5.1%. Similarly, under 60% baseline CHC prevalence the needed treatment coverage varies from 9.0-10.5%. Increasing HR coverage from 40% to 75%, reduces the required treatment coverage by 6.5-9.8% and 11.0-15.0% under 45% or 60% CHC prevalence, respectively. In settings with ?45% baseline CHC prevalence, expanding HR to 75% could prevent the disease from rebounding after elimination, irrespective of the type of the epidemic. In high chronic HCV prevalence, counseling interventions to reduce sharing are also needed to maintain the HCV incident cases in low levels. CONCLUSIONS:Harm reduction strategies have a vital role in HCV elimination strategy, as they reduce the required number of treatments to eliminate HCV and they provide sustainability after the elimination. The above underlines that HCV elimination strategies should be built upon the existing HR services, and argue for HR expansion in countries without services.

Project description:BackgroundPolice constitute a structural determinant of health and HIV risk of people who inject drugs (PWID), and negative encounters with law enforcement present significant barriers to PWID access to harm reduction services. Conversely, police may facilitate access via officer-led referrals, potentiating prevention of HIV, overdose, and drug-related harms. We aimed to identify police characteristics associated with support for officer-led referrals to addiction treatment services and syringe service programs (SSP). We hypothesized that officers who believe harm reduction services are contradictory to policing priorities in terms of safety and crime reduction will be less likely to support police referrals.MethodsBetween January and June 2018, police officers (n = 305) in Tijuana, Mexico, completed self-administered surveys about referrals to harm reduction services during the 24-month follow-up visit as part of the SHIELD police training and longitudinal cohort study. Log-binomial regression was used to estimate adjusted prevalence ratios and model policing characteristics and attitudes related to officers' support for including addiction treatment and SSP in referrals.ResultsRespondents were primarily male (89%), patrol officers (86%) with a median age of 38 years (IQR 33-43). Overall, 89% endorsed referral to addiction services, whereas 53% endorsed SSP as acceptable targets of referrals. Officers endorsing addiction services were less likely to be assigned to high drug use districts (adjusted prevalence ratio [APR] = 0.50, 95% CI 0.24, 1.08) and more likely to agree that methadone programs reduce crime (APR = 4.66, 95% CI 2.05, 9.18) than officers who did not support addiction services. Officers endorsing SSPs were younger (adjusted prevalence ratio [APR] = 0.96 95% CI 0.93, 0.98), less likely to be assigned to high drug use districts (APR = 0.50, 95% CI 0.29, 0.87), more likely to believe that methadone programs reduce crime (APR = 2.43, 95% CI 1.30, 4.55), and less likely to believe that SSPs increase risk of needlestick injury for police (APR = 0.44, 0.27, 0.71).ConclusionsBeliefs related to the occupational impact of harm reduction services in terms of officer safety and crime reduction are associated with support for referral to related harm reduction services. Efforts to deflect PWID from carceral systems toward harm reduction by frontline police should include measures to improve officer knowledge and attitudes about harm reduction services as they relate to occupational safety and law enforcement priorities.Trial registrationNCT02444403.

Project description:INTRODUCTION:The HIV epidemic in Tijuana, Mexico is concentrated in key populations, including people who inject drugs (PWID). However, HIV interventions among PWID are minimal, and federal funding was provided for compulsory abstinence programmes associated with HIV and overdose. Alternatively, opioid agonist therapy reduces overdose, reincarceration, HIV, while improving antiretroviral therapy (ART) outcomes. We assessed potential impact and synergies of scaled-up integrated ART and opioid agonist therapy, compared to scale-up of each separately, and potential harms of compulsory abstinence programmes on HIV and fatal overdose among PWID in Tijuana. METHODS:We developed a dynamic model of HIV transmission and overdose among PWID in Tijuana. We simulated scale-up of opioid agonist therapy from zero to 40% coverage among PWID. We evaluated synergistic benefits of an integrated harm reduction and ART scale-up strategy (40% opioid agonist therapy coverage and 10-fold ART recruitment), compared to scale-up of each intervention alone or no scale-up of low coverage ART and no harm reduction). We additionally simulated compulsory abstinence programmes (associated with 14% higher risk of receptive syringe sharing and 76% higher odds of overdose) among PWID. RESULTS:Without intervention, HIV incidence among PWID could increase from 0.72 per 100 person-years (PY) in 2020 to 0.92 per 100 PY in 2030. Over ten years, opioid agonist therapy scale-up could avert 31% (95% uncertainty interval (UI): 18%, 46%) and 22% (95% UI: 10%, 28%) new HIV infections and fatal overdoses, respectively, with the majority of HIV impact from the direct effect on HIV transmission due to low ART coverage. Integrating opioid agonist therapy and ART scale-up provided synergistic benefits, with opioid agonist therapy effects on ART recruitment/retention averting 9% more new infections compared to ART scale-up alone. The intervention strategy could avert 48% (95% UI: 26%, 68%) of new HIV infections and one-fifth of fatal overdoses over ten years. Conversely, compulsory abstinence programmes could increase HIV and overdoses. CONCLUSIONS:Integrating ART with opioid agonist therapy could provide synergistic benefits and prevent HIV and overdoses among PWID in Tijuana, whereas compulsory abstinence programmes could cause harm. Policymakers should consider the benefits of integrating harm reduction and HIV services for PWID.

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Project description:BACKGROUND:As countries embark on public health-oriented drug law reform, health impact evaluations are needed. In 2012, Mexico mandated the narcomenudeo reform, which depenalised the possession of small amounts of drugs and instituted drug treatment instead of incarceration. We investigated the past and future effect of this drug law reform on HIV incidence in people who inject drugs in Tijuana, Mexico. METHODS:In this epidemic modelling study, we used data from the El Cuete IV cohort study to develop a deterministic model of injecting and sexual HIV transmission in people who inject drugs in Tijuana between 2012 and 2030. The population was stratified by sex, incarceration status, syringe confiscation by the police, HIV stage, and exposure to drug treatment or rehabilitation (either opioid agonist treatment or compulsory drug abstinence programmes). We modelled the effect of these exposures on HIV risk in people who inject drugs, estimating the effect of observed and potential future reform enforcement levels. FINDINGS:In 2011, prior to the narcomenudeo reform, 547 (75%) of 733 people who inject drugs in the El Cuete cohort reported having ever been incarcerated, on average five times since starting injecting. Modelling estimated the limited reform implementation averted 2% (95% CI 0·2-3·0) of new HIV infections in people who inject drugs between 2012 and 2017. If implementation reduced incarceration in people who inject drugs by 80% from 2018 onward, 9% (95% CI 4-16) of new HIV infections between 2018 and 2030 could be averted, with 21% (10-33) averted if people who inject drugs were referred to opioid agonist treatment instead of being incarcerated. Referral to compulsory drug abstinence programmes instead of prison could have a lower or potentially negative impact with -2% (95% CI -23 to 9) infections averted. INTERPRETATION:Mexican drug law reform has had a negligible effect on the HIV epidemic among people who inject drugs in Tijuana. However, appropriate implementation could markedly reduce HIV incidence if linked to opioid agonist treatment. Unfortunately, compulsory drug abstinence programmes are the main type of drug rehabilitation available and their expansion could potentially increase HIV transmission. FUNDING:National Institute on Drug Abuse, UC San Diego Center for AIDS Research.