Prevention and treatment produced large decreases in HIV incidence in a model of people who inject drugs

A Review of Network Models for HIV Spread

BACKGROUND

HIV/AIDS has been a global health crisis for over 4 decades. Network models, which simulate human behavior and intervention impacts, have become an essential tool in guiding HIV prevention strategies and policies. However, no comprehensive survey of network models in HIV research has been conducted. This article fills that gap, offering a summary of past work and future directions to engage more researchers and inform policy related to eliminating HIV.

SETTING

Network models explicitly represent interactions between individuals, making them well-suited to study HIV transmission dynamics. Two primary modeling paradigms exist: a mechanistic approach from applied mathematics and a statistical approach from the social sciences. Each has distinct strengths and weaknesses, which should be understood for effective application to HIV research.

METHODS

We conducted a systematic review of network models used in HIV research, detailing the model types, populations, interventions, behaviors, datasets, and software used, while identifying potential future research directions.

RESULTS

Network models are particularly valuable for studying behaviors central to HIV transmission, such as partner selection and treatment adherence. Unlike traditional models, they focus on individual behaviors, aligning them with clinical practice. However, more accurate network data are needed for better model calibration and actionable insights.

CONCLUSIONS

This article serves as a point of reference for HIV researchers interested in applying network models and understanding their limitations. To our knowledge, this is the most comprehensive review of HIV network models to date.

Agent-based model projections for reducing HIV infection among MSM: Prevention and care pathways to end the HIV epidemic in Chicago, Illinois

Our objective is to improve local decision-making for strategies to end the HIV epidemic using the newly developed Levers of HIV agent-based model (ABM). Agent-based models use computer simulations that incorporate heterogeneity in individual behaviors and interactions, allow emergence of systemic behaviors, and extrapolate into the future. The Levers of HIV model (LHM) uses Chicago neighborhood demographics, data on sex-risk behaviors and sexual networks, and data on the prevention and care cascades, to model local dynamics. It models the impact of changes in local preexposure prophylaxis (PrEP) and antiretroviral treatment (ART) (ie, levers) for meeting Illinois' goal of "Getting to Zero" (GTZ) -reducing by 90% new HIV infections among men who have sex with men (MSM) by 2030. We simulate a 15-year period (2016-2030) for 2304 distinct scenarios based on 6 levers related to HIV treatment and prevention: (1) linkage to PrEP for those testing negative, (2) linkage to ART for those living with HIV, (3) adherence to PrEP, (4) viral suppression by means of ART, (5) PrEP retention, and (6) ART retention. Using tree-based methods, we identify the best scenarios at achieving a 90% HIV infection reduction by 2030. The optimal scenario consisted of the highest levels of ART retention and PrEP adherence, next to highest levels of PrEP retention, and moderate levels of PrEP linkage, achieved 90% reduction by 2030 in 58% of simulations. We used Bayesian posterior predictive distributions based on our simulated results to determine the likelihood of attaining 90% HIV infection reduction using the most recent Chicago Department of Public Health surveillance data and found that projections of the current rate of decline (2016-2019) would not achieve the 90% (p = 0.0006) reduction target for 2030. Our results suggest that increases are needed at all steps of the PrEP cascade, combined with increases in retention in HIV care, to approach 90% reduction in new HIV diagnoses by 2030. These findings show how simulation modeling with local data can guide policy makers to identify and invest in efficient care models to achieve long-term local goals of ending the HIV epidemic.

Nurse Practitioner-Led Integrated Rapid Access to HIV Prevention for People Who Inject Drugs (iRaPID): Protocol for a Pilot Randomized Controlled Trial

BACKGROUND

The ongoing volatile opioid epidemic remains a significant public health concern, alongside continued outbreaks of HIV and hepatitis C virus among people who inject drugs. The limited access to and scale-up of medications for opioid use disorder (MOUD) among people who inject drugs, coupled with multilevel barriers to pre-exposure prophylaxis (PrEP) uptake, makes it imperative to integrate evidence-based risk reduction and HIV prevention strategies in innovative ways. To address this need, we developed an integrated rapid access to HIV prevention program for people who inject drugs (iRaPID) that incorporates same-day PrEP and MOUD for this population.

OBJECTIVE

The primary objective of this pilot study is to assess the feasibility and acceptability of the program and evaluate its preliminary efficacy on PrEP and MOUD uptake for a future randomized controlled trial (RCT). We also aim to explore information on the implementation of the program in a real-world setting using a type I hybrid implementation trial design.

METHODS

Using a type I hybrid implementation trial design, we are pilot testing the nurse practitioner-led iRaPID program while exploring information on its implementation in a real-world setting. Specifically, we will assess the feasibility and acceptability of the iRaPID program and evaluate its preliminary efficacy on PrEP and MOUD uptake in a pilot RCT. The enrolled 50 people who inject drugs will be randomized (1:1) to either iRaPID or treatment as usual (TAU). Behavioral assessments will occur at baseline, and at 1, 3, and 6 months. Additionally, we will conduct a process evaluation of the delivery and implementation of the iRaPID program to collect information for future implementation.

RESULTS

Recruitment began in July 2021 and was completed in August 2022. Data collection is planned through February 2023. The Institutional Review Boards at Yale University and the University of Connecticut approved this study (2000028740).

CONCLUSIONS

This prospective pilot study will test a nurse practitioner-led, integrated HIV prevention program that incorporates same-day PrEP and MOUD for people who inject drugs. This low-threshold protocol delivers integrated prevention via one-stop shopping under the direction of nurse practitioners. iRaPID seeks to overcome barriers to delayed PrEP and MOUD initiation, which is crucial for people who inject drugs who have had minimal access to evidence-based prevention.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04531670; https://clinicaltrials.gov/ct2/show/NCT04531670.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/42585.

Using Microsimulation Modeling to Inform EHE Implementation Strategies in Los Angeles County

BACKGROUND

Pre-exposure prophylaxis (PrEP) is essential to ending HIV. Yet, uptake remains uneven across racial and ethnic groups. We aimed to estimate the impacts of alternative PrEP implementation strategies in Los Angeles County.

SETTING

Men who have sex with men, residing in Los Angeles County.

METHODS

We developed a microsimulation model of HIV transmission, with inputs from key local stakeholders. With this model, we estimated the 15-year (2021-2035) health and racial and ethnic equity impacts of 3 PrEP implementation strategies involving coverage with 9000 additional PrEP units annually, above the Status-quo coverage level. Strategies included PrEP allocation equally (strategy 1), proportionally to HIV prevalence (strategy 2), and proportionally to HIV diagnosis rates (strategy 3), across racial and ethnic groups. We measured the degree of relative equalities in the distribution of the health impacts using the Gini index (G) which ranges from 0 (perfect equality, with all individuals across all groups receiving equal health benefits) to 1 (total inequality).

RESULTS

HIV prevalence was 21.3% in 2021 [Black (BMSM), 31.1%; Latino (LMSM), 18.3%, and White (WMSM), 20.7%] with relatively equal to reasonable distribution across groups (G, 0.28; 95% confidence interval [CI], 0.26 to 0.34). During 2021-2035, cumulative incident infections were highest under Status-quo (n = 24,584) and lowest under strategy 3 (n = 22,080). Status-quo infection risk declined over time among all groups but remained higher in 2035 for BMSM (incidence rate ratio, 4.76; 95% CI: 4.58 to 4.95), and LMSM (incidence rate ratio, 1.74; 95% CI: 1.69 to 1.80), with the health benefits equally to reasonably distributed across groups (G, 0.32; 95% CI: 0.28 to 0.35). Relative to Status-quo, all other strategies reduced BMSM-WMSM and BMSM-LMSM disparities, but none reduced LMSM-WMSM disparities by 2035. Compared to Status-quo, strategy 3 reduced the most both incident infections (% infections averted: overall, 10.2%; BMSM, 32.4%; LMSM, 3.8%; WMSM, 3.5%) and HIV racial inequalities (G reduction, 0.08; 95% CI: 0.02 to 0.14).

CONCLUSIONS

Microsimulation models developed with early, continuous stakeholder engagement and inputs yield powerful tools to guide policy implementation.

Modeling the Impact of Social Determinants of Health on HIV

There is growing evidence for the key role of social determinants of health (SDOH) in understanding morbidity and mortality outcomes globally. Factors such as stigma, racism, poverty or access to health and social services represent complex constructs that affect population health via intricate relationships to individual characteristics, behaviors and disease prevention and treatment outcomes. Modeling the role of SDOH is both critically important and inherently complex. Here we describe different modeling approaches and their use in assessing the impact of SDOH on HIV/AIDS. The discussion is thematically divided into mechanistic models and statistical models, while recognizing the overlap between them. To illustrate mechanistic approaches, we use examples of compartmental models and agent-based models; to illustrate statistical approaches, we use regression and statistical causal models. We describe model structure, data sources required, and the scope of possible inferences, highlighting similarities and differences in formulation, implementation, and interpretation of different modeling approaches. We also indicate further needed research on representing and quantifying the effect of SDOH in the context of models for HIV and other health outcomes in recognition of the critical role of SDOH in achieving the goal of ending the HIV epidemic and improving overall population health.

A review of network simulation models of hepatitis C virus and HIV among people who inject drugs

Network modelling is a valuable tool for simulating hepatitis C virus (HCV) and HIV transmission among people who inject drugs (PWID) and assessing the potential impact of treatment and harm-reduction interventions. In this paper, we review literature on network simulation models, highlighting key structural considerations and questions that network models are well suited to address. We describe five approaches (Erdös-Rényi, Stochastic Block, Watts-Strogatz, Barabási-Albert, and Exponential Random Graph Model) used to model partnership formation with emphasis on the strengths of each approach in simulating different features of real-world PWID networks. We also review two important structural considerations when designing or interpreting results from a network simulation study: (1) dynamic vs. static network and (2) injection only vs. both injection and sexual networks. Dynamic network simulations allow partnerships to evolve and disintegrate over time, capturing corresponding shifts in individual and population-level risk behaviour; however, their high level of complexity and reliance on difficult-to-observe data has driven others to develop static network models. Incorporating both sexual and injection partnerships increases model complexity and data demands, but more accurately represents HIV transmission between PWID and their sexual partners who may not also use drugs. Network models add the greatest value when used to investigate how leveraging network structure can maximize the effectiveness of health interventions and optimize investments. For example, network models have shown that features of a given network and epidemic influence whether the greatest community benefit would be achieved by allocating hepatitis C or HIV treatment randomly, versus to those with the most partners. They have also demonstrated the potential for syringe services and "buddy sharing" programs to reduce disease transmission.

Psychometric Data Linking Across HIV and Substance Use Cohorts

Psychometric data linking of psychological and behavioral questionnaires can facilitate the harmonization of data across HIV and substance use cohorts. Using data from the Collaborating Consortium of Cohorts Producing NIDA Opportunities (C3PNO), we demonstrate how to capitalize on previous linking work with a common linked depression metric across multiple questionnaires. Cohorts were young men who have sex with men (MSM), substance-using MSM, HIV/HCV cocaine users, and HIV-positive patients. We tested for differential item functioning (DIF) by comparing C3PNO cohort data with general population data. We also fit a mixed-effects model for depression, entering HIV-status and recent opioid/heroin use as fixed effects and cohort as a random intercept. Our results suggest a minimal level of DIF between the C3PNO cohorts and general population samples. After linking, descriptive statistics show a wide range of depression score means across cohorts. Our model confirmed an expected positive relationship between substance use and depression, though contrary to expectations, no significant association with HIV status. The study reveals the likely role of cohort differences, associated patient characteristics, study designs, and administration settings.

Projecting the impact of equity-based preexposure prophylaxis implementation on racial disparities in HIV incidence among MSM

BACKGROUND

It is unknown what levels of preexposure prophylaxis (PrEP) use are needed to reduce racial disparities in HIV incidence among men who have sex with men (MSM). Using an agent-based model, we quantified the impact of achieving PrEP coverage targets grounded in equity on racial disparities in HIV incidence among MSM in an urban setting in the Southeastern United States.

METHODS

An agent-based model was adapted to simulate HIV transmission in a network of Black/African American and White MSM aged 18-39 years in the Atlanta-Sandy Springs-Roswell metropolitan area over 10 years (2015-2024). Scenarios simulated coverage levels consistent with targets based on the ratio of the number of individuals using PrEP to the number of individuals newly diagnosed in a calendar year (i.e., the 'PrEP-to-need ratio'), ranging from 1 to 10. Incidence rate ratios and differences were calculated as measures of disparities.

RESULTS

Without PrEP, the model predicted a rate ratio of 3.82 and a rate difference of 4.50 comparing HIV incidence in Black/African American and White MSM, respectively. Decreases in the rate ratio of at least 50% and in the rate difference of at least 75% were observed in all scenarios in which the PrEP-to-need ratio among Black/African American MSM was 10, regardless of the value among White MSM.

CONCLUSION

Significant increases in PrEP use are needed among Black/African American MSM to reduce racial disparities in HIV incidence. PrEP expansion must be coupled with structural interventions to address vulnerability to HIV infection among Black/African American MSM.

Opioid agonist treatment scale-up and the initiation of injection drug use: A dynamic modeling analysis

BACKGROUND

Injection drug use (IDU) is associated with multiple health harms. The vast majority of IDU initiation events (in which injection-naïve persons first adopt IDU) are assisted by a person who injects drugs (PWID), and as such, IDU could be considered as a dynamic behavioral transmission process. Data suggest that opioid agonist treatment (OAT) enrollment is associated with a reduced likelihood of assisting with IDU initiation. We assessed the association between recent OAT enrollment and assisting IDU initiation across several North American settings and used dynamic modeling to project the potential population-level impact of OAT scale-up within the PWID population on IDU initiation.

METHODS AND FINDINGS

We employed data from a prospective multicohort study of PWID in 3 settings (Vancouver, Canada [n = 1,737]; San Diego, United States [n = 346]; and Tijuana, Mexico [n = 532]) from 2014 to 2017. Site-specific modified Poisson regression models were constructed to assess the association between recent (past 6 month) OAT enrollment and history of ever having assisted an IDU initiation with recently assisting IDU initiation. Findings were then pooled using linear mixed-effects techniques. A dynamic transmission model of IDU among the general population was developed, stratified by known factors associated with assisting IDU initiation and relevant drug use behaviors. The model was parameterized to a generic North American setting (approximately 1% PWID) and used to estimate the impact of increasing OAT coverage among PWID from baseline (approximately 21%) to 40%, 50%, and 60% on annual IDU initiation incidence and corresponding PWID population size across a decade. From Vancouver, San Diego, and Tijuana, respectively, 4.5%, 5.2%, and 4.3% of participants reported recently assisting an IDU initiation, and 49.4%, 19.7%, and 2.1% reported recent enrollment in OAT. Recent OAT enrollment was significantly associated with a 45% lower likelihood of providing recent IDU initiation assistance among PWID (relative risk [RR] 0.55 [95% CI 0.36-0.84], p = 0.006) compared to those not recently on OAT. Our dynamic model predicts a baseline mean of 1,067 (2.5%-97.5% interval [95% I 490-2,082]) annual IDU initiations per 1,000,000 individuals, of which 886 (95% I 406-1,750) are assisted by PWID. Based on our observed statistical associations, our dynamic model predicts that increasing OAT coverage from approximately 21% to 40%, 50%, or 60% among PWID could reduce annual IDU initiations by 11.5% (95% I 2.4-21.7), 17.3% (95% I 5.6-29.4), and 22.8% (95% I 8.1-36.8) and reduce the PWID population size by 5.4% (95% I 0.1-12.0), 8.2% (95% I 2.2-16.9), and 10.9% (95% I 3.2-21.8) relative to baseline, respectively, in a decade. Less impact occurs when the protective effect of OAT is diminished, when a greater proportion of IDU initiations are unassisted by PWID, and when average IDU career length is longer. The study's main limitations are uncertainty in the causal pathway between OAT enrollment and assisting with IDU initiation and the use of a simplified model of IDU initiation.

CONCLUSIONS

In addition to its known benefits on preventing HIV, hepatitis C virus (HCV), and overdose among PWID, our modeling suggests that OAT scale-up may also reduce the number of IDU initiations and PWID population size.

Decreasing HIV transmissions to African American women through interventions for men living with HIV post-incarceration: An agent-based modeling study

Background

Incarceration and HIV disproportionately impact African American communities. The mass incarceration of African American men is hypothesized to increase HIV acquisition risk for African American women. Interventions optimizing HIV care engagement and minimizing sexual risk behaviors for men living with HIV post-incarceration may decrease HIV incidence.

Methods

Using an agent-based model, we simulated a sexual and injection drug using network representing the African American population of Philadelphia. We compared intervention strategies for men living with HIV post-incarceration by the number of averted HIV transmissions to women within the community. Three interventions were evaluated: a 90-90-90 scenario scaling up HIV testing, ART provision, and ART adherence; a behavioral intervention decreasing sexual risk behaviors; and a combination intervention involving both.

Results

The status quo scenario projected 2,836 HIV transmissions to women over twenty years. HIV transmissions to women decreased by 29% with the 90-90-90 intervention, 23% with the behavioral intervention, and 37% with both. The number of men living with HIV receiving the intervention needed in order to prevent a single HIV transmission ranged between 6 and 10.

Conclusion

Interventions to improve care engagement and decrease sexual risk behaviors post-incarceration for men living with HIV have the potential to decrease HIV incidence within African American heterosexual networks.

Integrated Models of Care for Individuals with Opioid Use Disorder: How Do We Prevent HIV and HCV?

Purpose of Review

To describe models of integrated and co-located care for opioid use disorder (OUD), hepatitis C (HCV), and HIV.

Recent Findings

The design and scale-up of multidisciplinary care models that engage, retain, and treat individuals with HIV, HCV, and OUD are critical to preventing continued spread of HIV and HCV. We identified 17 models within primary care (N = 3), HIV specialty care (N = 5), opioid treatment programs (N = 6), transitional clinics (N = 2), and community-based harm reduction programs (N = 1), as well as two emerging models.

Summary

Key components of such models are the provision of (1) medication-assisted treatment for OUD, (2) HIV and HCV treatment, (3) HIV pre-exposure prophylaxis, and (4) behavioral health services. Research is needed to understand differences in effectiveness between co-located and fully integrated care, combat the deleterious racial and ethnic legacies of the “War on Drugs,” and inform the delivery of psychiatric care. Increased access to harm reduction services is crucial.

Electronic supplementary material

The online version of this article (10.1007/s11904-018-0396-x) contains supplementary material, which is available to authorized users.

Systems Modeling to Advance the Promise of Data Science in Epidemiology

Systems science models use computer-based algorithms to model dynamic interactions between study units within and across levels and are characterized by nonlinear and feedback processes. They are particularly valuable approaches that complement the traditional epidemiologic toolbox in cases in which real data are not available and in cases in which traditional epidemiologic methods are limited by issues such as interference, spatial dependence, and dynamic feedback processes. In this commentary, we propose 2 key contributions that systems models can make to epidemiology: 1) the ability to test assumptions about underlying mechanisms that give rise to population distributions of disease; and 2) help in identifying the types of interventions that have the greatest potential to reduce population rates of disease in the future or in new sites where they have not yet been implemented. We discuss central challenges in the application of systems science approaches in epidemiology, propose potential solutions, and predict future developments in the role that systems science can play in epidemiology.

Potential drivers of HIV acquisition in African-American women related to mass incarceration: an agent-based modelling study

Background

The United States has the highest incarceration rate in the world. Incarceration can increase HIV risk behaviors for individuals involved with the criminal justice system and may be a driver of HIV acquisition within the community.

Methods

We used an agent-based model to simulate HIV transmission in a sexual-contact network representing heterosexual African American men and women in Philadelphia to identify factors influencing the impact of male mass incarceration on HIV acquisition in women. The model was calibrated using surveillance data and assumed incarceration increased the number of sexual contacts and decreased HIV care engagement for men post-release. Incarceration of a partner increased the number of sexual contacts for women. We compared a counterfactual scenario with no incarceration to scenarios varying key parameters to determine what factors drove HIV acquisition in women.

Results

Setting the duration of male high-risk sexual behavior to two years post-release increased the number of HIV transmissions to women by more than 20%. Decreasing post-release HIV care engagement and increasing HIV acquisition risk attributable to sexually transmitted infections (STIs) also increased the number of HIV transmissions to women. Changing the duration of risk behavior for women, the proportion of women engaging in higher risk behavior, and the relative risk of incarceration for HIV-infected men had minimal impact.

Conclusion

The mass incarceration of African American men can increase HIV acquisition in African American women on a population-level through factors including post-release high-risk behaviors, disruption of HIV care engagement among formerly incarcerated men, and increased STI prevalence. These findings suggest that the most influential points of intervention may be programs seeking to reduce male risk behaviors and promote HIV care engagement post-release, as well as STI testing and treatment programs for recently incarcerated men, as well as women with incarcerated partners.

Electronic supplementary material

The online version of this article (10.1186/s12889-018-6304-x) contains supplementary material, which is available to authorized users.

Combination interventions for Hepatitis C and Cirrhosis reduction among people who inject drugs: An agent-based, networked population simulation experiment

Hepatitis C virus (HCV) infection is endemic in people who inject drugs (PWID), with prevalence estimates above 60% for PWID in the United States. Previous modeling studies suggest that direct acting antiviral (DAA) treatment can lower overall prevalence in this population, but treatment is often delayed until the onset of advanced liver disease (fibrosis stage 3 or later) due to cost. Lower cost interventions featuring syringe access (SA) and medically assisted treatment (MAT) have shown mixed results in lowering HCV rates below current levels. However. little is known about the potential cumulative effects of combining DAA and MAT treatment. While simulation experiments can reveal likely long-term effects, most prior simulations have been performed on closed populations of model agents—a scenario quite different from the open, mobile populations known to most health agencies. This paper uses data from the Centers for Disease Control’s National HIV Behavioral Surveillance project, IDU round 3, collected in New York City in 2012 to parameterize simulations of open populations. To test the effect of combining DAA treatment with SA/MAT participation, multiple, scaled implementations of the two intervention strategies were simulated. Our results show that, in an open population, SA/MAT by itself has only small effects on HCV prevalence, while DAA treatment by itself can lower both HCV and HCV-related advanced liver disease prevalence. More importantly, the simulation experiments suggest that combinations of the two strategies can, when implemented together and at sufficient levels, dramatically reduce HCV incidence. We conclude that adopting SA/MAT implementations alongside DAA interventions can play a critical role in reducing the long-term consequences of ongoing HCV infection.

Rare diseases under different levels of economic analysis: current activities, challenges and perspectives

Rare diseases imply clinical and economic burden as well as a significant challenge for health systems. One relevant objective of the activities planned within the European Reference Network on Rare and Complex Connective Tissue and Musculoskeletal Diseases (ERN ReCONNET) is to address the economic dimensions of rare diseases to identify, develop and suggest strategies to improve research and patients' access to orphan drugs (ODs) and highly specialised health technologies. This paper presents a preliminary review of the existing policies on rare diseases in the countries of the Network members. It also introduces and discusses the theme of how to perform health economic evaluations of rare diseases and of existing or new treatments for rare diseases. To obtain a preliminary overview aiming at defining the state of the art of rare diseases policies and initiatives in ERN ReCONNET countries, we collected and analysed the rare diseases national plans of all the eight countries of the ERN ReCONNET participants. The preliminary overview that has been performed showed that in all the ERN ReCONNET countries are in place national plans for rare diseases; however, heterogeneity exists in the reimbursement of ODs, direct provision by the healthcare system, involvement of patients' associations in decision making and implementation of clinical practice guidelines.

Integrated Bio-behavioral Approach to Improve Adherence to Pre-exposure Prophylaxis and Reduce HIV Risk in People Who Use Drugs: A Pilot Feasibility Study

This study reports the feasibility, acceptability, and preliminary efficacy of the bio-behavioral community-friendly health recovery program-an integrated, HIV prevention intervention to improve pre-exposure prophylaxis (PrEP) adherence and HIV-risk reduction behaviors among high-risk people who use drugs. We used a within-subjects, pretest-posttest follow-up design to recruit participants, who were HIV-uninfected, methadone-maintained and reported HIV-risk behaviors and had initiated PrEP (n = 40; males: 55%). Participants were assessed at baseline (T₀), immediately post-intervention (4 weeks: T₄) and 4 weeks post-intervention (T₈). Immediately after completing the four weekly intervention groups, participants underwent a post-intervention assessment including in-depth qualitative interviews. Feasibility was high, assessed by participant willingness to enroll (90.1%) and retention (95%). Results showed that participants were highly satisfied and perceived the intervention as valuable and acceptable [mean: 81.3 (range 0-100)]. Significant enhancements in self-reported PrEP adherence [F(2,74) = 7.500, p = 0.001] and PrEP-related knowledge [F(2,74) = 3.828, p = 0.026] were observed. Drug-related (e.g., injection of drugs, sharing of injection equipment) and sex-related (e.g., number of sexual partners, condomless sex) risk behaviors were reduced, while information, motivation, and behavioral skills (IMB) constructs increased. The results support feasibility and high acceptability and support further examination of the efficacy of this combination bio-behavioral intervention in a prospective clinical trial.

Exploring the Use of Pre-exposure Prophylaxis (PrEP) for HIV Prevention Among High-Risk People Who Use Drugs in Treatment

Introduction: Despite unequivocal evidence supporting the use of pre-exposure prophylaxis (PrEP), its scale-up has been gradual overall, and nearly absent among people who use drugs (PWUD). In the present study, we implemented the use of PrEP, as a part of an integrated HIV prevention approach, and explored the experiences and attitudes related to PrEP use among PWUD.

Methods: Between September 2016 and July 2017, we recruited 40 HIV-uninfected, methadone-maintained people, who reported HIV-risk behaviors, and were currently taking PrEP. We conducted both quantitative and in-depth semi-structured qualitative interviews that primarily focused on experiences, attitudes, acceptability, disclosure status, risk compensation-related attitudes, and barriers related to PrEP adherence.

Results: Results showed that participants were highly satisfied and perceived PrEP as valuable and acceptable for HIV prevention. Participants reported high adherence to PrEP. The most highly endorsed facilitators to PrEP adherence were use of memory aids, no out-of-pocket cost, perceived benefit, and support from social network. The barriers to adherence included side-effects, stigmatization, requirement of daily dosing, and accessibility of PrEP services. Additionally, participants expressed disagreement with the overall risk compensation-related attitudes (i.e., decreased personal concern about engaging in HIV risk behavior due to their perception that PrEP is now fully protecting them from contracting HIV) and indicated no increased engagement in risk behaviors while on PrEP.

Conclusions: The results from the current study provide preliminary evidence supporting the successful integration of PrEP within the substance abuse treatment setting, where high risk PWUD are concentrated.

HIV/AIDS and the African-American Community 2018: a Decade Call to Action

HIV/AIDS disproportionately affects African-Americans more than any other racial or ethnic group in the USA. Currently representing only 12% of the US population, African-Americans now comprise close to half of the total reported HIV/AIDS cases in the USA according to the Centers for Disease Control and Prevention since the initial reporting of HIV/AIDS. In this paper, we examined the prevalence and current direction of the HIV/AIDS epidemic in the African-American community especially in comparison to our first call to action in 2008. The situation remains dire and broader attention is necessary from the public health and medical sectors who serve the majority of African-American populations and the community at-large to work towards closing this health disparity gap. This paper thus recommends an action plan for community leaders (i.e., the public health sector, policy makers, public health practitioners, and other stakeholders) to reduce the disparity.

Measuring Acceptability and Preferences for Implementation of Pre-Exposure Prophylaxis (PrEP) Using Conjoint Analysis: An Application to Primary HIV Prevention Among High Risk Drug Users

Although people who use drugs (PWUD) are one of the key risk populations who could benefit from the use of pre-exposure prophylaxis (PrEP), to date, little attention has been given to incorporating PrEP into HIV prevention approaches targeting this underserved group. This study investigated the acceptability of PrEP based on a number of known PrEP attributes among high-risk PWUD in a drug treatment setting. A total of 400 HIV-negative PWUD, who reported drug- and/or sex-related risk behaviors were recruited from a methadone clinic to complete a stated preference (full-profile conjoint) survey. Participants ranked the eight hypothetical PrEP program scenarios with varied combinations of six attributes related to PrEP (cost, dosing, efficacy, side-effects, treatment setting, and frequency of HIV testing). SPSS conjoint procedure was used to estimate the relative importance of each attribute and preferences across eight possible PrEP delivery programs. PrEP acceptability ranged from 30.6 to 86.3% with a mean acceptability of 56.2% across the eight hypothetical PrEP program scenarios. The PrEP program scenario with the highest acceptability had the following attribute levels: insurance covered, daily dosing, 95% effective, no side-effects, treatment at HIV clinic, and HIV testing needed every 6 months. The cost associated with PrEP was the most important attribute (relative importance score: RIS = 38.8), followed by efficacy (RIS = 20.5) and side effects (RIS = 11.9); other attributes had no significant effect. Our findings reported a high acceptability of PrEP in response to different PrEP program scenarios with different attribute profiles. As the result of having this information, researchers and policymakers will be better equipped for evidence informed targeting and dissemination efforts to optimize PrEP uptake among this underserved population.

Network Viral Load: A Critical Metric for HIV Elimination

BACKGROUND

Associations have been observed between an aggregate viral load measure, the community viral load, and new HIV diagnoses. The community viral load aggregates viral loads within chosen geographic areas, restricting inferences about HIV acquisition risk to these areas. We develop a more precise metric, the network viral load (NVL), to measure the composite viral load within a risk network of a HIV-negative individual.

METHODS

We examined the relationship between NVL and HIV infection among young men who have sex with men in Chicago, United States. Networks were generated using respondent-driven sampling. NVL was defined as the prevalence of viremic individuals in one's risk network, characterized as those with a viral load ≥20 k copies per milliliter. Permutation tests were conducted to account for dependency.

RESULTS

After controlling for total connections, age, substance use during sex, syphilis diagnosis (previous 12 months), and frequency of condomless anal sex (previous 6 months), we found a positive association between NVL and HIV infection. Compared with a network with all HIV-seronegative members, the odds of HIV infection with an NVL of <10% viremia were 1.85 (95% confidence interval: 1.18 to 2.92) times higher and those with an NVL of ≥10% viremia were 2.73 (95% confidence interval: 1.54 to 4.85) times higher.

CONCLUSIONS

We found a positive association between NVL and HIV seroprevalence. Although limited in its ability to infer causality, NVL could have substantial public health implications for persons most at risk for HIV infection, given that this novel metric avoids overreliance on individual level behavior or broad community indices.

Agent-Based Modeling in Public Health: Current Applications and Future Directions

Agent-based modeling is a computational approach in which agents with a specified set of characteristics interact with each other and with their environment according to predefined rules. We review key areas in public health where agent-based modeling has been adopted, including both communicable and noncommunicable disease, health behaviors, and social epidemiology. We also describe the main strengths and limitations of this approach for questions with public health relevance. Finally, we describe both methodologic and substantive future directions that we believe will enhance the value of agent-based modeling for public health. In particular, advances in model validation, comparisons with other causal modeling procedures, and the expansion of the models to consider comorbidity and joint influences more systematically will improve the utility of this approach to inform public health research, practice, and policy.

Rare diseases under different levels of economic analysis: current activities, challenges and perspectives

Rare diseases imply clinical and economic burden as well as a significant challenge for health systems. One relevant objective of the activities planned within the European Reference Network on Rare and Complex Connective Tissue and Musculoskeletal Diseases (ERN ReCONNET) is to address the economic dimensions of rare diseases to identify, develop and suggest strategies to improve research and patients' access to orphan drugs (ODs) and highly specialised health technologies. This paper presents a preliminary review of the existing policies on rare diseases in the countries of the Network members. It also introduces and discusses the theme of how to perform health economic evaluations of rare diseases and of existing or new treatments for rare diseases. To obtain a preliminary overview aiming at defining the state of the art of rare diseases policies and initiatives in ERN ReCONNET countries, we collected and analysed the rare diseases national plans of all the eight countries of the ERN ReCONNET participants. The preliminary overview that has been performed showed that in all the ERN ReCONNET countries are in place national plans for rare diseases; however, heterogeneity exists in the reimbursement of ODs, direct provision by the healthcare system, involvement of patients' associations in decision making and implementation of clinical practice guidelines.

Treatment of HIV for the Prevention of Transmission in Discordant Couples and at the Population Level

The scientific breakthrough proving that antiretroviral therapy (ART) can halt heterosexual HIV transmission came in the form of a landmark clinical trial conducted among serodiscordant couples. Study findings immediately informed global recommendations for the use of treatment as prevention in serodiscordant couples. The extent to which these findings are generalizable to other key populations or to groups exposed to HIV through nonsexual transmission routes (i.e., anal intercourse or unsafe injection of drugs) has since driven a large body of research. This review explores the history of HIV research in serodiscordant couples, the implications for management of couples, subsequent research on treatment as prevention in other key populations, and challenges in community implementation of these strategies.

Examining the Acceptability of mHealth Technology in HIV Prevention Among High-Risk Drug Users in Treatment

Despite promising trends of the efficacy of mobile health (mHealth) based strategies to a broad range of health conditions, very few if any studies have been done in terms of the examining the use of mHealth in HIV prevention efforts among people who use drugs in treatment. Thus, the goal of this study was to gain insight into the real-world acceptance of mHealth approaches among high-risk people who use drugs in treatment. A convenience sample of 400 HIV-negative drug users, who reported drug- and/or sex-related risk behaviors, were recruited from a methadone clinic in New Haven, Connecticut. Participants completed standardized assessments of drug- and sex-related risk behaviors, neurocognitive impairment (NCI), and measures of communication technology access and utilization, and mHealth acceptance. We found a high prevalence of current ownership and use of mobile technologies, such as cell phone (91.5%) including smartphone (63.5%). Participants used mobile technologies to communicate mostly through phone calls (M = 4.25, SD = 1.24), followed by text messages (M = 4.21, SD = 1.29). Participants expressed interest in using mHealth for medication reminders (72.3%), receive information about HIV (65.8%), and to assess drug-related (72.3%) and sex-related behaviors (64.8%). Furthermore, participants who were neurocognitively impaired were more likely to use cell phone without internet and show considerable interest in using mHealth as compared to those without NCI. The findings from this study provide empirical evidence that mHealth-based programs, specifically cell phone text messaging-based health programs, may be acceptable to this high-risk population.

Developing an Integrated, Brief Biobehavioral HIV Prevention Intervention for High-Risk Drug Users in Treatment: The Process and Outcome of Formative Research

To date, HIV prevention efforts have largely relied on singular strategies (e.g., behavioral or biomedical approaches alone) with modest HIV risk-reduction outcomes for people who use drugs (PWUD), many of whom experience a wide range of neurocognitive impairments (NCI). We report on the process and outcome of our formative research aimed at developing an integrated biobehavioral approach that incorporates innovative strategies to address the HIV prevention and cognitive needs of high-risk PWUD in drug treatment. Our formative work involved first adapting an evidence-based behavioral intervention-guided by the Assessment-Decision-Administration-Production-Topical experts-Integration-Training-Testing model-and then combining the behavioral intervention with an evidence-based biomedical intervention for implementation among the target population. This process involved eliciting data through structured focus groups (FGs) with key stakeholders-members of the target population (n = 20) and treatment providers (n = 10). Analysis of FG data followed a thematic analysis approach utilizing several qualitative data analysis techniques, including inductive analysis and cross-case analysis. Based on all information, we integrated the adapted community-friendly health recovery program-a brief evidence-based HIV prevention behavioral intervention-with the evidence-based biomedical component [i.e., preexposure prophylaxis (PrEP)], an approach that incorporates innovative strategies to accommodate individuals with NCI. This combination approach-now called the biobehavioral community-friendly health recovery program-is designed to address HIV-related risk behaviors and PrEP uptake and adherence as experienced by many PWUD in treatment. This study provides a complete example of the process of selecting, adapting, and integrating the evidence-based interventions-taking into account both empirical evidence and input from target population members and target organization stakeholders. The resultant brief evidence-based biobehavioral approach could significantly advance primary prevention science by cost-effectively optimizing PrEP adherence and HIV risk reduction within common drug treatment settings.

Interest in use of mHealth technology in HIV prevention and associated factors among high-risk drug users enrolled in methadone maintenance program

The adoption of mobile technologies for health (mHealth) in healthcare has grown considerably in recent years, but systematic assessment of interest in the use of mHealth in HIV prevention efforts among people who use drugs (PWUD) is lacking. We therefore examined interest in use of mHealth technology in HIV prevention and associated individual-level factors among high-risk PWUD enrolled in methadone maintenance program. A total of 400 HIV-negative PWUD, who reported drug- and/or sex-related risk behaviors completed a standardized assessment using audio computer assisted self-interview (ACASI). Results revealed significant interest in using mHealth-based approaches for specific purposes, including: to receive medication reminders (72.3%), to receive information about HIV risk reduction (65.8%), and to assess HIV risk behaviors (76.5%). Multivariate analysis showed that interest in receiving medication reminders was associated with currently taking medication and being neurocognitively impaired, whereas interest in receiving HIV-risk reduction information was associated with being non-white, married, and perceiving the person was at high-risk for contracting HIV. Similarly, participants' interested in using mHealth for HIV risk behavior assessment was associated with having recently visited a healthcare provider and exhibiting depressive symptoms. Overall, this study demonstrated that high-risk PWUD are interested in using mHealth-based tools as a key part of an HIV prevention approach within a common type of drug treatment settings. Thus, formative research on preferences for design and functionality of mHealth-based HIV prevention tools are now needed, followed by practical development, implementation, and evaluation of these new intervention strategies.

Willingness to Use Pre-Exposure Prophylaxis (PrEP): An Empirical Test of the Information-Motivation-Behavioral Skills (IMB) Model among High-Risk Drug Users in Treatment

Evidence from recent pre-exposure prophylaxis (PrEP) trials has demonstrated its safety and efficacy in significantly reducing the risk of HIV acquisition for those who are at considerable risk of acquiring HIV infection. With a rapid increase in the amount of research on the efficacy of PrEP for HIV prevention, complementary research on the willingness to use PrEP has grown, especially among MSM, but limited research has been focused among people who use drugs (PWUD). As part of the formative process, we utilized the information-motivation-behavioral skills (IMB) model of health behavior change to characterize and guide intervention development for promoting willingness to use PrEP among high-risk PWUD. The analysis included 400 HIV-negative high-risk PWUD enrolled in a community-based methadone maintenance treatment who reported drug- and/or sex-related HIV risk behaviors in the past 6-months. Analyses revealed support for the IMB model as PrEP-related behavioral skills were found to mediate the influence of PrEP-related information and motivation on willingness to use PrEP. The results provide evidence as to the utility of the IMB model to increase willingness to use PrEP among high-risk PWUD. It therefore makes an important contribution to our understanding of the applicability of theoretically-grounded models of willingness to use PrEP among high-risk PWUD, who are one of the key risk populations who could benefit from the use of PrEP.

Intent to Use Preexposure Prophylaxis (PrEP), HIV Risk Behaviors, and Self-Report Neurocognitive Symptoms by High-Risk Drug Users: A Mediation Analysis

Neurocognitive impairment (NCI) and HIV risk are significant correlates of intent to use preexposure prophylaxis (PrEP). The extent to which similar outcomes could occur when these factors operate together, particularly for people who use drugs (PWUD), remains an important unanswered question. We therefore sought evidence that HIV risk behavior mediated the relationship between NCI and intent to use PrEP in high-risk PWUD in treatment. HIV-uninfected, methadone-maintained people who reported HIV-risk behaviors were enrolled (n = 400). Variables of interest (NCI, HIV risk behaviors, intent to use PrEP) were assessed using audio computer-assisted self-interview. We found preliminary evidence of indirect effect of HIV risk behaviors, such that NCI had an increased impact on intent to use PrEP via HIV risk behaviors. As a result of having this information, clinicians and researchers will be better equipped for evidence-informed targeting and dissemination efforts to optimize PrEP uptake by this underserved population.

Correlates of willingness to initiate pre-exposure prophylaxis and anticipation of practicing safer drug- and sex-related behaviors among high-risk drug users on methadone treatment

BACKGROUND

Although people who use drugs (PWUD) are key populations recommended to receive pre-exposure prophylaxis (PrEP) to prevent HIV, few data are available to guide PrEP delivery in this underserved group. We therefore examined the willingness to initiate PrEP and the anticipation of HIV risk reduction while on PrEP among high-risk PWUD.

METHODS

In a cross-sectional study of 400 HIV-negative, opioid dependent persons enrolled in a methadone program and reporting recent risk behaviors, we examined independent correlates of being willing to initiate PrEP.

RESULTS

While only 72 (18%) were aware of PrEP, after being given a description of it, 251 (62.7%) were willing to initiate PrEP. This outcome was associated with having neurocognitive impairment (aOR=3.184, p=0.004) and higher perceived HIV risk (aOR=8.044, p<0.001). Among those willing to initiate PrEP, only 12.5% and 28.2%, respectively, indicated that they would always use condoms and not share injection equipment while on PrEP. Consistent condom use was associated with higher income (aOR=8.315, p=0.016), always using condoms with casual partners (aOR=6.597, p=0.001), and inversely associated with ongoing drug injection (aOR=0.323, p=0.027). Consistent safe injection, however, was inversely associated with age (aOR=0.948, p=0.035), ongoing drug injection (aOR=0.342, p<0.001), and perceived HIV risk (aOR=0.191, p=0.019).

CONCLUSIONS

While willingness to initiate PrEP was high and correlated with being at elevated risk for HIV, anticipated higher risk behaviors in this group even while on PrEP suggests that the next generation of HIV prevention approaches may need to combine biomedical and behavioral components to sustain HIV risk reduction over time.

The Interaction of Risk Network Structures and Virus Natural History in the Non-spreading of HIV Among People Who Inject Drugs in the Early Stages of the Epidemic

This article explores how social network dynamics may have reduced the spread of HIV-1 infection among people who inject drugs during the early years of the epidemic. Stochastic, discrete event, agent-based simulations are used to test whether a "firewall effect" can arise out of self-organizing processes at the actor level, and whether such an effect can account for stable HIV prevalence rates below population saturation. Repeated simulation experiments show that, in the presence of recurring, acute, and highly infectious outbreaks, micro-network structures combine with the HIV virus's natural history to reduce the spread of the disease. These results indicate that network factors likely played a significant role in the prevention of HIV infection within injection risk networks during periods of peak prevalence. They also suggest that social forces that disturb network connections may diminish the natural firewall effect and result in higher rates of HIV.

Acute HIV infection transmission among people who inject drugs in a mature epidemic setting

OBJECTIVE

Estimates for the contribution of transmission arising from acute HIV infections (AHIs) to overall HIV incidence vary significantly. Furthermore, little is known about AHI-attributable transmission among people who inject drugs (PWID), including the extent to which interventions targeting chronic infections (e.g. HAART as prevention) are limited by AHI transmission. Thus, we estimated the proportion of transmission events attributable to AHI within the mature HIV epidemic among PWID in New York City (NYC).

DESIGN

Modeling study.

METHODS

We constructed an interactive sexual and injecting transmission network using an agent-based model simulating the HIV epidemic in NYC between 1996 and 2012. Using stochastic microsimulations, we cataloged transmission from PWID based on the disease stage of index agents to determine the proportion of infections transmitted during AHI (in primary analyses, assumed to last 3 months).

RESULTS

Our calibrated model approximated the epidemiological features of the mature HIV epidemic in NYC between 1996 and 2012. Annual HIV incidence among PWID dropped from approximately 1.8% in 1996 to 0.7% in 2012. Over the 16-year period, AHI accounted for 4.9% (10th/90th percentile: 0.1-12.3%) of incident HIV cases among PWID. The annualized contribution of AHI increased over this period from 3.6% in 1996 to 5.9% in 2012.

CONCLUSION

Our results suggest that, in mature epidemics such as NYC, between 3% and 6% of transmission events are attributable to AHI among PWID. Current HIV treatment as prevention strategies are unlikely to be substantially affected by AHI-attributable transmission among PWID populations in mature epidemic settings.

Treatment Engagement Moderates the Effect of Neurocognitive Impairment on Antiretroviral Therapy Adherence in HIV-Infected Drug Users in Treatment

Neurocognitive impairment (NCI) and treatment engagement (TE) have been shown to significantly predict antiretroviral therapy (ART) adherence, but no studies have explored the ways and the extent to which similar outcomes might occur when these factors operate together, particularly for people who use drugs (PWUDs). We sought to discover whether TE moderated the effect of NCI on adherence to ART in HIV-infected individuals. One hundred sixteen HIV-infected, methadone-maintained people who reported HIV risk behaviors were enrolled in the study. Variables of interest (NCI, ART adherence, TE) were assessed using audio computer-assisted self-interview. Results revealed a significant interactive effect of NCI and TE on ART adherence, which supported the moderation effect. Findings from post hoc analyses showed that NCI was negatively associated with adherence to ART at low levels of TE. Findings suggest the need to accommodate individual NCI and improve TE as a means to enhance ART adherence in HIV-infected PWUDs.

Can the Heterosexual HIV Epidemic be Eliminated in South Africa Using Combination Prevention? A Modeling Analysis

Little is known about how combining efficacious interventions for human immunodeficiency virus (HIV) prevention could lead to HIV elimination. We used an agent-based simulation model, the HIV calibrated dynamic model, to assess the potential for HIV elimination in South Africa. We examined several scenarios (from continuation of the current status quo to perfect achievement of targets) with differing combinations of male condom use, adult male circumcision, HIV testing, and early antiretroviral therapy (ART). We varied numerous parameters, including the proportion of adult males circumcised, the frequency of condom use during sex acts, acceptance of HIV testing, linkage to health care, criteria for ART initiation, ART viral suppression rates, and loss to follow-up. Maintaining current levels of combination prevention would lead to increasing HIV incidence and prevalence in South Africa, while the perfect combination scenario was projected to eliminate HIV on a 50-year time scale from 2013 to 2063. Perfecting testing and treatment, without changing condom use or circumcision rates, resulted in an 89% reduction in HIV incidence but not elimination. Universal adult male circumcision alone resulted in a 21% incidence reduction within 20 years. Substantial decreases in HIV incidence are possible from sufficient uptake of both primary prevention and ART, but with continuation of the status quo, HIV elimination in South Africa is unlikely within a 50-year time scale.

Modeling a Theory-Based Approach to Examine the Influence of Neurocognitive Impairment on HIV Risk Reduction Behaviors Among Drug Users in Treatment

Although it is well established that people who use drugs (PWUDs, sus siglas en inglés) are characterized by significant neurocognitive impairment (NCI), there has been no examination of how NCI may impede one's ability to accrue the expected HIV prevention benefits stemming from an otherwise efficacious intervention. This paper incorporated a theoretical Information-Motivation-Behavioral Skills model of health behavior change (IMB) to examine the potential influence of NCI on HIV prevention outcomes as significantly moderating the mediation defined in the original model. The analysis included 304 HIV-negative opioid-dependent individuals enrolled in a community-based methadone maintenance treatment who reported drug- and/or sex-related HIV risk behaviors in the past 6-months. Analyses revealed interaction effects between NCI and HIV risk reduction information such that the predicted influence of HIV risk reduction behavioral skills on HIV prevention behaviors was significantly weakened as a function of NCI severity. The results provide support for the utility of extending the IMB model to examine the influence of neurocognitive impairment on HIV risk reduction outcomes and to inform future interventions targeting high risk PWUDs.

Social Determinants of Population Health: A Systems Sciences Approach

Population distributions of health emerge from the complex interplay of health-related factors at multiple levels, from the biological to the societal level. Individuals are aggregated within social networks, affected by their locations, and influenced differently across time. From aggregations of individuals, group properties can emerge, including some exposures that are ubiquitous within populations but variant across populations. By combining a focus on social determinants of health with a conceptual framework for understanding how genetics, biology, behavior, psychology, society, and environment interact, a systems science approach can inform our understanding of the underlying causes of the unequal distribution of health across generations and populations, and can help us identify promising approaches to reduce such inequalities. In this paper, we discuss how systems science approaches have already made several substantive and methodological contributions to the study of population health from a social epidemiology perspective.

Understanding the effects of different HIV transmission models in individual-based microsimulation of HIV epidemic dynamics in people who inject drugs

We investigated how different models of HIV transmission, and assumptions regarding the distribution of unprotected sex and syringe-sharing events ('risk acts'), affect quantitative understanding of HIV transmission process in people who inject drugs (PWID). The individual-based model simulated HIV transmission in a dynamic sexual and injecting network representing New York City. We constructed four HIV transmission models: model 1, constant probabilities; model 2, random number of sexual and parenteral acts; model 3, viral load individual assigned; and model 4, two groups of partnerships (low and high risk). Overall, models with less heterogeneity were more sensitive to changes in numbers risk acts, producing HIV incidence up to four times higher than that empirically observed. Although all models overestimated HIV incidence, micro-simulations with greater heterogeneity in the HIV transmission modelling process produced more robust results and better reproduced empirical epidemic dynamics.

Does the theory-driven program affect the risky behavior of drug injecting users in a healthy city? A quasi-experimental study

BACKGROUND

The horror of HIV/AIDS as a non-curable, grueling disease is a destructive issue for every country. Drug use, shared needles and unsafe sex are closely linked to the transmission of HIV/AIDS. Modification or changing unhealthy behavior through educational programs can lead to HIV prevention. The aim of this study was to evaluate the efficiency of theory-based education intervention on HIV prevention transmission in drug addicts.

METHODS

In this quasi-experimental study, 69 male drug injecting users were entered in to the theory- based educational intervention. Data were collected using a questionnaire, before and 3 months after four sessions (group discussions, lecture, film displaying and role play) of educational intervention.

RESULTS

The findings signified that the mean scores of constructs (self-efficacy, susceptibility, severity and benefit) significantly increased after the educational intervention, and the perceived barriers decreased (p< 0.001). Also, the history of HIV testing was reported to be 9% before the intervention, while the rate increased to 88% after the intervention.

CONCLUSION

The present research offers a primary founding for planning and implementing a theory based educational program to prevent HIV/AIDS transmission in drug injecting addicts. This research revealed that health educational intervention improved preventive behaviors and the knowledge of HIV/AIDS participants.

To Treat or to Prevent?: Reducing the Population Burden of Violence-related Post-traumatic Stress Disorder

BACKGROUND

Violence-related post-traumatic stress disorder (PTSD) remains a prevalent and disabling psychiatric disorder in urban areas. However, the most effective allocation of resources into prevention and treatment to reduce this problem is unknown. We contrasted the impact of two interventions on violence-related PTSD: (1) a population-level intervention intended to prevent violence (i.e., hot-spot policing), and (2) an individual-level intervention intended to shorten PTSD duration (i.e., cognitive-behavioral therapy-CBT).

METHODS

We used agent-based modeling to simulate violence and PTSD in New York City under four scenarios: (1) no intervention, (2) targeted policing to hot spots of violence, (3) increased access to CBT for people who suffered from violence-related PTSD, and (4) a combination of the two interventions.

RESULTS

Combined prevention and treatment produced the largest decrease in violence-related PTSD prevalence: hot-spot policing plus a 50% increase in CBT for 5 years reduced the annual prevalence of violence-related PTSD from 3.6% (95% confidence interval = 3.5%, 3.6%) to 3.4% (3.3%, 3.5%). It would have been necessary to implement hot-spot policing or to increase CBT by 200% for 10 years for either intervention to achieve the same reduction in isolation.

CONCLUSIONS

This study provides an empirically informed demonstration that investment in combined strategies that target social determinants of mental illness and provide evidence-based treatment to those affected by psychiatric disorders can produce larger reductions in the population burden from violence-related PTSD than either preventive or treatment interventions alone. However, neither hot-spot policing nor CBT, alone or combined, will produce large shifts in the population prevalence of violence-related PTSD.

A non-inferiority trial of an evidence-based secondary HIV prevention behavioral intervention compared to an adapted, abbreviated version: Rationale and intervention description

BACKGROUND

Real-world clinical settings like addiction treatment programs are ill-equipped to deploy and sustain the existing resource-demanding evidence-based interventions (EBIs) that target HIV-infected people who use drugs (PWUDs), and this has left a critical void in current HIV prevention efforts. In response to this unmet need, we have conducted formative research in addiction treatment settings that has resulted in Holistic Health for HIV (3H+) - an empirically adapted, substantially abbreviated version of Holistic Health Recovery Program (HHRP+), a CDC-recommended EBI targeting HIV-infected PWUDs.

METHODS

Using a non-inferiority randomized controlled trial design, we will determine whether the abbreviated 3H+ intervention is comparable (i.e., within a 10% margin) and cost-effective relative to the original HHRP+ intervention in terms of reducing HIV risk behaviors and improving antiretroviral therapy (ART) adherence among HIV-infected PWUDs in addiction treatment who report drug- or sex-related HIV risk behaviors.

CONCLUSIONS

This article provides a description of the development and adaptation of the 3H+ intervention, the innovative non-inferiority comparative experimental design for testing the 3H+ to the HHRP+. Furthermore, it provides empirical evidence from a formal cost-effectiveness analysis justifying the cost-effectiveness of the 3H+ intervention when compared to the HHRP+ intervention. If confirmed to be comparable and more cost-effective, as hypothesized, the 3H+ intervention has the potential to be readily and immediately integrated within common clinical settings where large numbers of HIV-infected PWUDs receive clinical services.

Evaluating HIV prevention strategies for populations in key affected groups: the example of Cabo Verde

OBJECTIVES

We used an individual-based model to evaluate the effects of hypothetical prevention interventions on HIV incidence trajectories in a concentrated, mixed epidemic setting from 2011 to 2021, and using Cabo Verde as an example.

METHODS

Simulations were conducted to evaluate the extent to which early HIV treatment and optimization of care, HIV testing, condom distribution, and substance abuse treatment could eliminate new infections (i.e., reduce incidence to less than 10 cases per 10,000 person-years) among non-drug users, female sex workers (FSW), and people who use drugs (PWUD).

RESULTS

Scaling up all four interventions resulted in the largest decreases in HIV, with estimates ranging from 1.4 (95 % CI 1.36-1.44) per 10,000 person-years among non-drug users to 8.2 (95 % CI 7.8-8.6) per 10,000 person-years among PWUD in 2021. Intervention scenarios prioritizing FWS and PWUD also resulted in HIV incidence estimates at or below 10 per 10,000 person-years by 2021 for all population sub-groups.

CONCLUSIONS

Our results suggest that scaling up multiple interventions among entire population is necessary to achieve elimination. However, prioritizing key populations with this combination prevention strategy may also result in a substantial decrease in total incidence.