HIV infection during limited versus combined HIV prevention programs for IDUs in New York City: the importance of transmission behaviors

Is your syringe services program cost-saving to society? A methodological case study

BACKGROUND

While there is a general acceptance among public health officials and policy-makers that syringe services programs can be effective in reducing HIV transmission among persons who inject drugs, local syringe services programs are often asked to provide economic justifications for their activities. A cost-effectiveness study, estimating the cost of preventing one HIV infection, would be the preferred methods for addressing this economic question, but few local syringe services programs have the needed data, staff and epidemiologic modeling resources needed for a cost-effectiveness study. We present a method for estimating a threshold value for the number of HIV infections prevented above which the program will be cost-saving to society. An intervention is considered "cost-saving" when it leads to a desirable health outcome a lower cost than the alternative.

METHODS

The research literature on the effectiveness of syringe services programs in controlling HIV transmission among persons who inject drugs and guidelines for syringe services program that are "functioning very well" were used to estimate the cost-saving threshold at which a syringe services program becomes cost-saving through preventing HIV infections versus lifetime treatment of HIV. Three steps are involved: (1) determining if HIV transmission in the local persons who inject drugs (PWID) population is being controlled, (2) determining if the local syringe services program is functioning very well, and then (3) dividing the annual budget of the syringe services program by the lifetime cost of treating a single HIV infection.

RESULTS

A syringe services program in an area with controlled HIV transmission (with HIV incidence of 1/100 person-years or less), functioning very well (with high syringe coverage, linkages to other services, and monitoring the local drug use situation), and an annual budget of $500,000 would need to prevent only 3 new HIV infections per year to be cost-saving.

CONCLUSIONS

Given the high costs of treating HIV infections, syringe services programs that are operating according to very good practices ("functioning very well") and in communities in which HIV transmission is being controlled among persons who inject drugs, will almost certainly be cost-saving to society.

Is the severity of the Great Recession's aftershocks correlated with changes in access to the combined prevention environment among people who inject drugs?

BACKGROUND

The 2008 Recession was a global event that led to funding cuts for programs and services in the United States; though this recession officially ended in 2009, its aftershocks continued through 2012. We evaluated the relationship between the severity of the Great Recession's aftermath and spatial access to combined prevention services (i.e. HIV testing, syringe service programs, substance use disorder treatment program) for people who inject drugs (PWID) living in 19 metropolitan statistical areas (MSAs) in the United States.

METHODS

The unit of analysis was the ZIP code; we sampled ZIP codes in these 19 MSAs where ≥1 PWID lived in 2009 and 2012, according to the CDC's National HIV Behavioral Surveillance. We used administrative data to describe the combined prevention environment (i.e., spatial access to HIV testing) for each ZIP code, and measured the severity of the recession's aftermath in each ZIP code, and in the counties and MSAs where these ZIP codes were located. Multilevel modeling estimated associations between changes in the aftermath of the Great Recession and ZIP code-level changes in spatial access to combined prevention services from 2009 to 2012.

RESULTS

675 ZIP codes located in 36 counties and 19 MSAs were included in this analysis. From 2009 to 2012, 21% of ZIP code areas lost access to combined prevention services and 14% gained access. ZIP codes with higher poverty rates relative to their respective MSAs were less likely to lose access (aOR: 0.91; 95% CI: 0.88, 0.95) and more likely to gain access (aOR: 1.05; 95% CI: 1.01, 1.09); there is some evidence to suggest the former association was attenuated for ZIP codes with higher percentages of non-Hispanic white residents.

CONCLUSION

Combined prevention services for PWID living in these 675 ZIP codes demonstrated resilience in the aftermath of the Great Recession. Future research should explore whether community-based and federal HIV prevention initiatives contributed to this resilience, particularly in areas with higher concentrations of people of color.

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.

Hepatitis C virus prevalence and estimated incidence among new injectors during the opioid epidemic in New York City, 2000-2017: Protective effects of non-injecting drug use

OBJECTIVE

Assess hepatitis C virus (HCV) prevalence and incidence among person who began injecting drugs during the opioid epidemic in New York City (NYC) and identify possible new directions for reducing HCV infection among persons who inject drugs.

METHODS

846 persons who began injecting drugs between 2000 and 2017 were recruited from persons entering Mount Sinai Beth Israel substance use treatment programs. A structured interview was administered and HCV antibody testing conducted. Protective effects of non-injecting drug use were examined among persons who "reversed transitioned" to non-injecting drug use and persons who used non-injected heroin in addition to injecting.

RESULTS

Participants were 79% male, 41% White, 15% African-American, 40% Latinx, with a mean age of 35. Of those who began injecting in 2000 or later, 97 persons (11%) "reverse transitioned" back to non-injecting drug use. Reverse transitioning was strongly associated with lower HCV seroprevalence (30% versus 47% among those who continued injecting, p < 0.005). Among those who continued injecting, HCV seropositivity was inversely associated with current non-injecting heroin use (AOR = 0.72, 95%CI 0.52-0.99). HCV incidence among persons continuing to inject was estimated as 13/100 person-years. HCV seropositive persons currently injecting cocaine were particularly likely to report behavior likely to transmit HCV.

CONCLUSIONS

Similar to other locations in the US, NYC is experiencing high rates of HCV infection among persons who have begun injecting since 2000. New interventions that facilitate substitution of non-injecting for injecting drug use and that reduce transmission behavior among HCV seropositives may provide additional methods for reducing HCV transmission.

Continued Transmission of HIV Among Young Adults Who Inject Drugs in San Francisco: Still Room for Improvement

We measured HIV incidence rate, trend and risk factors in 564 HIV-negative young people (< 30 years) who inject drugs (PWID) in San Francisco between 2000 and 2014. HIV incidence was 0.93/100 person-years (PY; 95% CI 0.50, 1.73). Incidence varied between 0.62/100 PY in 2000-2002 and 1.06/100 PY in 2012-2014 (P for trend = 1.0). HIV incidence varied significantly (P < 0.01) by race/ethnicity: among Hispanics it was 8.19/100 PY (95% CI 3.41, 19.68), African-Americans 4.59/100 PY (95% CI 1.15, 18.37), and Whites 0.26/100 PY (95% CI 0.06, 1.03). Male participants who reported sex with men (MSM) had higher HIV incidence (2.63/100 PY; 95% CI 1.31, 5.25) compared to males who did not report MSM (0.50/100 PY; 95% CI 0.12, 1.99) (P = 0.01). Despite an overall stable HIV incidence trend, incidence was elevated among African-American and Hispanic PWID, and men who have sex with men. Addressing prevention needs in these key populations is critical for the goal of eliminating HIV transmission.

Racial Differences in HIV and HCV Risk Behaviors, Transmission, and Prevention Knowledge among Non-Treatment-Seeking Individuals with Opioid Use Disorder

In light of New York's recently reinforced strategy to end the AIDS epidemic by expanding testing, treatment, and access to pre-exposure prophylaxis (PrEP), we assessed drug use and sexual risk behaviors, along with HIV/Hepatitis C virus (HCV) transmission and prevention knowledge among non-treatment-seeking adults with opioid use disorder (OUD) in New York City. Over the course of 18 months, volunteers screening for research studies in the Opioid Laboratory at the New York State Psychiatric Institute completed a locally developed self-assessment questionnaire. A total of 138 adults with OUD (24 female, 114 male) with a mean age of 46.5 years (SD = 9.5 yrs) were assessed. Significant differences among the four racial/ethnic subgroups (n = 65 African-Americans, n = 34 Hispanics, n = 31 Caucasians or Whites, n = 8 Multiracial) were found. Whites were the youngest (p = 0.001), most frequently injecting drugs (p < 0.001), and engaged more often in risky drug use and sexual behaviors, although their virus transmission knowledge was comparable to that of the other subgroups. Few participants had heard about PrEP. White opioid users showed the most risk behaviors among races/ethnicities, despite comparable prevention knowledge. Better HIV/HCV prevention interventions targeting individuals with opioid use disorders who are not currently in treatment would be desirable, given their large health burden.

Cost-Effectiveness of the 'One4All' HIV Linkage Intervention in Guangxi Zhuang Autonomous Region, China

BACKGROUND

In Guangxi Zhuang Autonomous Region, China, an estimated 80% of newly-identified antiretroviral therapy (ART)-eligible patients are not engaged in ART. Delayed ART uptake ultimately translates into high rates of HIV morbidity, mortality, and transmission. To enhance HIV testing receipt and subsequent treatment uptake in Guangxi, the Chinese Center for Disease Control and Prevention (CDC) executed a cluster-randomized trial to assess the effectiveness and cost-effectiveness of a streamlined HIV testing algorithm (the One4All intervention) in 12 county-level hospitals.

OBJECTIVE

To determine the incremental cost-effectiveness of the One4All intervention delivered at county hospitals in Guangxi, China, compared to the current standard of care (SOC).

PERSPECTIVE

Health System.

TIME HORIZON

1-, 5-and 25-years.

METHODS

We adapted a dynamic, compartmental HIV transmission model to simulate HIV transmission and progression in Guangxi, China and identify the economic impact and health benefits of implementing the One4All intervention in all Guangxi hospitals. The One4All intervention algorithm entails rapid point-of-care HIV screening, CD4 and viral load testing of individuals presenting for HIV screening, with same-day results and linkage to counselling. We populated the model with data from the One4All trial (CTN-0056), China CDC HIV registry and published reports. Model outcomes were HIV incidence, mortality, costs, quality-adjusted life years (QALYs), and the incremental cost-effectiveness ratio (ICER) of the One4All intervention compared to SOC.

RESULTS

The One4All testing intervention was more costly than SOC (CNY 2,182 vs. CNY 846), but facilitated earlier ART access, resulting in delayed disease progression and mortality. Over a 25-year time horizon, we estimated that introducing One4All in Guangxi would result in 802 averted HIV cases and 1629 averted deaths at an ICER of CNY 11,678 per QALY gained. Sensitivity analysis revealed that One4All remained cost-effective at even minimal levels of effectiveness. Results were robust to changes to a range of parameters characterizing the HIV epidemic over time.

CONCLUSIONS

The One4All HIV testing strategy was highly cost-effective by WHO standards, and should be prioritized for widespread implementation in Guangxi, China. Integrating the intervention within a broader combination prevention strategy would enhance the public health response to HIV/AIDS in Guangxi.

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

In the United States, people who inject drugs continue to be at greatly increased risk of HIV infection. To estimate the effectiveness of various prevention scenarios, we modeled HIV transmission in a dynamic network of drug users and people who did not use drugs that was based on the New York Metropolitan Statistical Area population. We compared the projected HIV incidence in 2020 and 2040 if current approaches continue to be used to the incidence if one or more of the following hypothetical interventions were applied: increased HIV testing, improved access to substance abuse treatment, increased use of needle and syringe programs, scaled-up treatment as prevention, and a "high impact" combination scenario, consisting of all of the strategies listed above. No strategy completely eliminated HIV transmission. The high-impact combination strategy produced the largest decrease in HIV incidence-a 62 percent reduction compared to the status quo. Our results suggest that increased resources for and investments in multiple HIV prevention approaches will be required to eliminate HIV transmission among people who inject drugs.

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.

Incidence and prevalence of hepatitis c virus infection among persons who inject drugs in New York City: 2006-2013

BACKGROUND

Hepatitis C virus infection is a source of significant preventable morbidity and mortality among persons who inject drugs (PWID). We sought to assess trends in hepatitis C virus (HCV) infection among PWID from 2006 to 2013 in New York City (NYC).

METHODS

Annual cross-sectional surveys of PWID entering a large drug abuse treatment program were performed. Risk behavior questionnaires were administered, and HIV and HCV testing were conducted. Comparisons were made with prior prevalence and incidence estimates in 1990-1991 and 2000-2001 reflecting different periods of combined prevention and treatment efforts.

RESULTS

HCV prevalence among PWID (N: 1535) was 67% (95% CI: 66-70%) during the study period, and was not significantly different from that observed in 2000-2001. The estimated HCV incidence among new injectors (persons injecting for ≤6 years) during 2006-2013 was 19.5/100 PYO (95% CI: 17-23) and did not differ from that observed in 2000-2001 (18/100 PYO, 95% CI: 14-23/100).

CONCLUSIONS

Despite the expansion of combined prevention programming between 2000-2001 and 2006-2013, HCV prevalence remained high. Estimated HCV incidence among new injectors also remained high, and not significantly lower than in 2000-2001, indicating that expanded combined prevention efforts are needed to control the HCV epidemic among PWID in NYC.

Adherence to antiretroviral medications among persons who inject drugs in transitional, low and middle income countries: an international systematic review

Adherence to antiretroviral (ART) medication is vital to reducing morbidity and mortality among HIV positive persons. People who inject drugs (PWID) are at high risk for HIV infection in transitional/low/middle income countries (TLMIC). We conducted a systematic review of studies reporting adherence to ART among persons with active injection drug use and/or histories of injection drug use in TLMIC. Meta-regression was performed to examine relationships between location, adherence measurements, and follow-up period. Fifteen studies were included from seven countries. Adherence levels ranged from 33 to 97 %; mean weighted adherence was 72 %. ART adherence was associated with different methods of measuring adherence and studies conducted in Eastern Europe and East Asia. The great heterogeneity observed precludes generalization to TLMIC as a whole. Given the critical importance of ART adherence more research is needed on ART adherence among PWID in TLMIC, including the use of standardized methods for reporting adherence to ART.

Can HIV and Hepatitis C Virus Infection be Eliminated Among Persons Who Inject Drugs?

HIV and hepatitis C virus (HCV) infection are readily transmitted among persons who inject drugs. The HIV and HCV epidemics have expanded rapidly, becoming global health issues. Combined prevention has been implemented to reduce injection and sexual transmission of HIV and HCV among persons who inject drugs. Reductions in risky injection and sexual behavior have led to dramatic reductions in HIV in many countries. Whether comparable reductions in HCV transmission can be achieved has yet to be determined. Eliminating HIV and HCV among persons who inject drugs will require considerable resources and commitment, particularly in low and middle income countries.

Combined prevention for persons who inject drugs in the HIV epidemic in a transitional country: the case of Tallinn, Estonia

The study was undertaken to assess the potential effectiveness of combined HIV prevention on the very high seroprevalence epidemic among persons who inject drugs (PWID) in Tallinn, Estonia, a transitional country. Data from community-based cross-sectional (respondent-driven sampling) surveys of PWID in 2005, 2007, 2009, and 2011 were used together with mathematical modeling of injection-associated HIV acquisition to estimate changes in injection-related HIV incidence during these periods. Utilization of one, two, or three of the interventions available in the community (needle and syringes exchange program, antiretroviral treatment [ART], HIV testing, opioid substitution treatment) was reported by 42.5%, 30.5%, and 11.5% of HIV+ and 34.7%, 36.4%, and 5.7% of HIV- PWIDs, respectively, in 2011. The modeling results suggest that the combination of needle/syringe programs and provision of ART to PWID in Tallinn substantially reduced the incidence of HIV infection in this population, from an estimated 20.7/100 person-years in 2005 to 7.5/100 person-years in 2011. In conclusion, combined prevention targeting HIV acquisition and transmission-related risks among PWID in Tallinn has paralleled the downturn of the HIV epidemic in this population.

Substance abuse treatment utilization, HIV risk behaviors, and recruitment among suburban injection drug users in Long Island, New York

Prevention and treatment of injection drug use remains a public health concern. We used data from the 2005 Centers for Disease Control and prevention National HIV Behavioral Surveillance system to assess substance abuse treatment utilization, risk behaviors, and recruitment processes in a respondent driven sample of suburban injectors. Twelve service utilization and injection risk variables were analyzed using latent class analysis. Three latent classes were identified: low use, low risk; low use, high risk; and high use, moderate/high risk. In multivariate analysis, annual income <$15,000 (adjusted odds ratio (aOR) = 8.19 [95 % confidence interval (CI), 3.83-17.51]) and self-reported hepatitis C virus infection (aOR = 4.32, 95 % CI (1.84-10.17)) were significantly associated with class membership. Homophily, a measure of preferential recruitment showed that injectors with recent treatment utilization appear a more cohesive group than out-of-treatment injectors. Preferentially reaching injection drug users with high risk behaviors and no recent drug treatment history via respondent driven sampling will require future research.

Transitions from injecting to non-injecting drug use: potential protection against HCV infection

Transitions from injecting to non-injecting drug use have been reported from many different areas, particularly in areas with large human immunodeficiency virus (HIV) epidemics. The extent to which such transitions actually protect against HIV and HCV has not been determined. A cross-sectional survey with HIV and hepatitis C (HCV) testing was conducted with 322 former injectors (persons who had injected illicit drugs but permanently transitioned to non-injecting use) and 801 current injectors recruited in New York City between 2007 and 2012. There were no differences in HIV prevalence, while HCV prevalence was significantly lower among former injectors compared to current injectors. Years injecting functioned as a mediating variable linking former injector status to lower HCV prevalence. Transitions have continued well beyond the reduction in the threat of AIDS to injectors in the city. New interventions to support transitions to non-injecting drug use should be developed and supported by both drug treatment and syringe exchange programs.

Combined HIV prevention, the New York City condom distribution program, and the evolution of safer sex behavior among persons who inject drugs in New York City

Examine long term sexual risk behaviors among persons who inject drugs (PWID) in New York City following implementation of "combined" prevention programming, including condom social marketing. Quantitative interviews and human immunodeficiency virus (HIV) testing were conducted among PWID entering Beth Israel Medical Center drug treatment programs 1990-2012. Data were analyzed by four time periods corresponding to the cumulative implementation of HIV prevention interventions. 7,132 subjects were recruited from 1990 to 2012; little change in sexual behavior occurred among HIV seronegative subjects, while HIV seropositive subjects reported significant decreases in being sexually active and significant increases in consistent condom use. HIV transmission risk (being HIV positive and engaging in unprotected sex) declined from 14 % in 1990-1995 to 2 % in 2007-2012 for primary sexual partners and from 6 to 1 % for casual partners. Cumulative implementation of combined prevention programming for PWID was associated with substantial decreases in sexual risk behavior among HIV seropositives.

The potential for bridging: HIV status awareness and risky sexual behaviour of injection drug users who have non-injecting permanent partners in Ukraine

Objective

To quantify potential bridging of HIV transmission between the injection drug using subpopulation to the non-injection drug using population through unprotected heterosexual sex.

Design

Secondary analysis of cross-sectional data.

Methods

A sub-sample of participants who reported having a permanent partner who are not injection drug users and have not injected drugs in the past (N=1379) was selected from a survey implemented in 26 Ukrainian cities in 2011. This study evaluates the association between consistent condom use and awareness of HIV status as measured by rapid testing during the study (known/unknown HIV+, known/unknown HIV− and undetermined) among a sub-sample of male injection drug users (IDUs) who have a non-injecting permanent partner. Poisson regression, with robust variance estimates, was utilized to identify associations while adjusting for other factors.

Results

Reported consistent condom use varied between 15.5% (unknown HIV−) and 37.5% (known HIV+); average use was 19.3%. In multivariate analysis, males who were aware of their HIV+ status were more likely to report recent consistent condom use compared to those who were unaware of their HIV+ status. This association remains after adjustment for age, region, education level, years of injection, alcohol use, self-reported primary drug use and being an NGO client (prevalence ratio=1.65; 95% CI 1.03–2.64). No such association was found for those who were HIV−.

Conclusions

Our results regarding HIV-positive male IDUs reinforce previous findings that HIV testing and counselling may be an effective means of secondary prevention. Further research is needed to understand how to effectively promote safer sex behaviours for IDUs who are currently HIV−.

Effectiveness of structural-level needle/syringe programs to reduce HCV and HIV infection among people who inject drugs: a systematic review

Needle-syringe programs (NSP) have been effective in reducing HIV and hepatitis C (HCV) infection among people who inject drugs (PWID). Achieving sustainable reductions in these blood-borne infections requires addressing structural factors so PWID can legally access NSP services. Systematic literature searches collected information on NSP coverage and changes in HIV or HCV infection prevalence or incidence at the population level. Included studies had to document biomarkers (HIV or HCV) coupled with structural-level NSP, defined by a minimum 50 % coverage of PWID and distribution of 10 or more needles/syringe per PWID per year. Fifteen studies reported structural-level NSP and changes in HIV or HCV infection prevalence/incidence. Nine reported decreases in HIV prevalence, six in HCV infection prevalence, and three reported decreases in HIV incidence. The results support NSP as a structural-level intervention to reduce population-level infection and implementation of NSP for prevention and treatment of HIV and HCV infection.

30 Years on Selected Issues in the Prevention of HIV among Persons Who Inject Drugs

After 30 years of extensive research on human immunodeficiency virus (HIV) among persons who inject drugs (PWID), we now have a good understanding of the critical issues involved. Following the discovery of HIV in 1981, epidemics among PWID were noted in many countries, and consensus recommendations for interventions for reducing injection related HIV transmission have been developed. While high-income countries have continued to develop and implement new Harm Reduction programs, most low-/middle-income countries have implemented Harm Reduction at very low levels. Modeling of combined prevention programming including needle exchange (NSP) and antiretroviral therapy (ARV) suggests that NSP be given the highest priority. Future HIV prevention programming should continue to provide Harm Reduction programs for PWID coupled with interventions aimed at reducing sexual transmission. As HIV continues to spread in low- and middle-income countries, it is important to achieve and maintain high coverage of Harm Reduction programs in these locations. As PWID almost always experience multiple health problems, it will be important to address these multiple problems within a comprehensive approach grounded in a human rights perspective.

HIV infection among people who inject drugs: the challenge of racial/ethnic disparities

Racial/ethnic disparities in HIV infection, with minority groups typically having higher rates of infection, are a formidable public health challenge. In the United States, among both men and women who inject drugs, HIV infection rates are elevated among Hispanics and non-Hispanic Blacks. A meta-analysis of international research concluded that among persons who inject drugs, racial and ethnic minorities were twice as likely to acquire an HIV infection, though there was great variation across the individual studies. To examine strategies to reduce racial/ethnic disparities among persons who inject drugs, we reviewed studies on injection drug use and its role in HIV transmission. We identified four sets of evidence-based interventions that may reduce racial/ethnic disparities among persons who inject drugs: HIV counseling and testing, risk reduction services, access to antiretroviral therapy, and drug abuse treatment. Implementation of these services, however, is insufficient in many countries, including the United States. Persons who inject drugs appear to be changing drug use norms and rituals to reduce their risks. The challenges are to (a) develop a validated model of how racial/ethnic disparities in HIV infection arise, persist, and are reduced or eliminated over time and (b) implement evidence-based services on a sufficient scale to eliminate HIV transmission among all persons who inject drugs.

High coverage needle/syringe programs for people who inject drugs in low and middle income countries: a systematic review

BACKGROUND

Persons who inject drugs (PWID) are at an elevated risk for human immunodeficiency virus (HIV) and hepatitis C virus (HCV) infection. In many high-income countries, needle and syringe exchange programs (NSP) have been associated with reductions in blood-borne infections. However, we do not have a good understanding of the effectiveness of NSP in low/middle-income and transitional-economy countries.

METHODS

A systematic literature review based on PRISMA guidelines was utilized to collect primary study data on coverage of NSP programs and changes in HIV and HCV infection over time among PWID in low-and middle-income and transitional countries (LMICs). Included studies reported laboratory measures of either HIV or HCV and at least 50% coverage of the local injecting population (through direct use or through secondary exchange). We also included national reports on newly reported HIV cases for countries that had national level data for PWID in conjunction with NSP scale-up and implementation.

RESULTS

Studies of 11 NSPs with high-coverage from Bangladesh, Brazil, China, Estonia, Iran, Lithuania, Taiwan, Thailand and Vietnam were included in the review. In five studies HIV prevalence decreased (range -3% to -15%) and in three studies HCV prevalence decreased (range -4.2% to -10.2%). In two studies HIV prevalence increased (range +5.6% to +14.8%). HCV incidence remained stable in one study. Of the four national reports of newly reported HIV cases, three reported decreases during NSP expansion, ranging from -30% to -93.3%, while one national report documented an increase in cases (+37.6%). Estimated incidence among new injectors decreased in three studies, with reductions ranging from -11/100 person years at risk to -16/100 person years at risk.

CONCLUSIONS

While not fully consistent, the data generally support the effectiveness of NSP in reducing HIV and HCV infection in low/middle-income and transitional-economy countries. If high coverage is achieved, NSP appear to be as effective in LMICs as in high-income countries. Additional monitoring and evaluation research is needed for NSPs where reductions in HIV/HCV infection among PWID are not occurring in order to identify and correct contributing problems.

A complex systems approach to evaluate HIV prevention in metropolitan areas: preliminary implications for combination intervention strategies

BACKGROUND

HIV transmission among injecting and non-injecting drug users (IDU, NIDU) is a significant public health problem. Continuing propagation in endemic settings and emerging regional outbreaks have indicated the need for comprehensive and coordinated HIV prevention. We describe the development of a conceptual framework and calibration of an agent-based model (ABM) to examine how combinations of interventions may reduce and potentially eliminate HIV transmission among drug-using populations.

METHODOLOGY/PRINCIPAL FINDINGS

A multidisciplinary team of researchers from epidemiology, sociology, geography, and mathematics developed a conceptual framework based on prior ethnographic and epidemiologic research. An ABM was constructed and calibrated through an iterative design and verification process. In the model, "agents" represent IDU, NIDU, and non-drug users who interact with each other and within risk networks, engaging in sexual and, for IDUs, injection-related risk behavior over time. Agents also interact with simulated HIV prevention interventions (e.g., syringe exchange programs, substance abuse treatment, HIV testing) and initiate antiretroviral treatment (ART) in a stochastic manner. The model was constructed to represent the New York metropolitan statistical area (MSA) population, and calibrated by comparing output trajectories for various outcomes (e.g., IDU/NIDU prevalence, HIV prevalence and incidence) against previously validated MSA-level data. The model closely approximated HIV trajectories in IDU and NIDU observed in New York City between 1992 and 2002, including a linear decrease in HIV prevalence among IDUs. Exploratory results are consistent with empirical studies demonstrating that the effectiveness of a combination of interventions, including syringe exchange expansion and ART provision, dramatically reduced HIV prevalence among IDUs during this time period.

CONCLUSIONS/SIGNIFICANCE

Complex systems models of adaptive HIV transmission dynamics can be used to identify potential collective benefits of hypothetical combination prevention interventions. Future work will seek to inform novel strategies that may lead to more effective and equitable HIV prevention strategies for drug-using populations.

Are females who inject drugs at higher risk for HIV infection than males who inject drugs: an international systematic review of high seroprevalence areas

OBJECTIVE

There are multiple reasons why females who inject drugs may be more likely to become infected with HIV than males who inject drugs. Where this is the case, special HIV prevention programs for females would be needed.

DESIGN

International systematic review and meta-analysis of studies across 14 countries.

METHODS

Countries with high seroprevalence (>20%) HIV epidemics among persons who inject drugs (PWID) were identified from the Reference Group to the UN on HIV and Injecting Drug Use. Systematic literature reviews collected data on HIV prevalence by gender for these countries. Non-parametric and parametric tests along with meta-analytic techniques examined heterogeneity and differences in odds ratios (OR) across studies.

RESULTS

Data were abstracted from 117 studies in 14 countries; total sample size N = 128,745. The mean weighted OR for HIV prevalence among females to males was 1.18 [95% CI 1.10-1.26], with high heterogeneity among studies (I(2)= 70.7%). There was a Gaussian distribution of the log ORs across studies in the sample.

CONCLUSION

There was a significantly higher HIV prevalence among females compared to males who inject drugs in high seroprevalence settings, but the effect size is extremely modest. The high level of heterogeneity and the Gaussian distribution suggest multiple causes of differences in HIV prevalence between females and males, with a specific difference determined by local factors. Greater understanding of factors that may protect females from HIV infection may provide insights into more effective HIV prevention for both females and males who inject drugs.

Pharmacy staff characteristics associated with support for pharmacy-based HIV testing

OBJECTIVES

To determine support of in-pharmacy human immunodeficiency virus (HIV) testing among pharmacy staff and the individual-level characteristics associated with in-pharmacy HIV testing support.

DESIGN

Descriptive, nonexperimental, cross-sectional study.

SETTING

New York City (NYC) from January 2008 to March 2009.

PARTICIPANTS

480 pharmacy staff, including pharmacists, owners/managers, and technicians/clerks.

INTERVENTION

131 pharmacies registered in the Expanded Syringe Access Program (ESAP) completed a survey.

MAIN OUTCOME MEASURE

Support of in-pharmacy HIV testing.

RESULTS

Support of in-pharmacy HIV testing is high among pharmacy staff (79.4%). Pharmacy staff who supported in-pharmacy vaccinations were significantly more likely to support in-pharmacy HIV testing. Pharmacy staff who thought that selling syringes to injection drug users (IDUs) caused the community to be littered with dirty syringes were significantly less likely to support in-pharmacy HIV testing.

CONCLUSION

Support for in-pharmacy HIV testing was high among our sample of ESAP pharmacy staff actively involved in nonprescription syringe sales. These findings suggest that active ESAP pharmacy staff may be amenable to providing HIV counseling and testing to IDUs and warrants further investigation.

Differences in self-reported discrimination by primary type of drug used among New York City drug users

BACKGROUND

Illicit drug users experience various forms of discrimination which may vary by type of drug used, as there are different levels of stigma associated with different types of drugs.

OBJECTIVES

This study investigated self-report of perceived discrimination by primary type of drug used.

METHODS

This analysis used data from "Social Ties Associated with Risk of Transition into Injection Drug Use" (START), a cross-sectional study of recently initiated injection drug users (IDUs) and prospective study of heroin/crack/cocaine-using non-IDUs (n = 652). Using log binomial regression, the relationship between primary drug used (i.e., single drug used most often) with discrimination due to drug use was examined.

RESULTS

Heroin users were significantly more likely (Prevalence ratio (PR): 1.52 (95% Confidence interval (CI): 1.15-2.07)) to report discrimination due to drug use compared to cocaine users.

CONCLUSION AND SCIENTIFIC SIGNIFICANCE

More research is needed to understand the mechanism through which discrimination affects heroin users, and its potential relation with other discrimination-related outcomes, namely depression and drug treatment.

The urgency of providing comprehensive and integrated treatment for substance abusers with HIV

Substance abuse is linked to many new cases of HIV infection. Barriers such as the myth that drug users cannot adhere to HIV/AIDS treatment block progress in curbing the spread of HIV in that population. In this article we explain the need to aggressively seek out high-risk, hard-to-reach substance abusers and to offer them HIV testing, access to treatment, and the necessary support to remain in treatment--both for HIV and for substance abuse. We summarize evidence showing that injection drug users can successfully undergo HIV treatment; that many substance abusers adhere to antiretroviral therapy as well as do people who don't inject drugs; and that injection drug users who undergo substance abuse treatment are more likely to obtain and stay in treatment for their HIV infection. This evidence makes a strong case for integrating substance abuse treatment with HIV treatment programs and providing substance abusers with universal access to HIV treatment. But an integrated strategy will require changes in the health care system to overcome lingering obstacles that inhibit the merging of substance abuse treatment with HIV programs.

Potential role of safer injection facilities in reducing HIV and hepatitis C infections and overdose mortality in the United States

BACKGROUND

Safer injection facilities (SIFs) reduce risks associated with injecting drugs, particularly public injection and overdose mortality. They exist in many countries, but do not exist in the United States. We assessed several ethical, operational, and public health considerations for establishing SIFs in the United States.

METHOD

We used the six-factor Kass framework (goals, effectiveness, concerns, minimization of concerns, fair implementation, and balancing of benefits and concerns), summarized needs of persons who inject drugs in the United States, and reviewed global evidence for SIFs.

RESULTS

SIFs offer a hygienic environment to inject drugs, provide sterile injection equipment at time of injection, and allow for safe disposal of used equipment. Injection of pre-obtained drugs, purchased by persons who inject drugs, happens in a facility where trained personnel provide on-site counseling and referral to addiction treatment and health care and intervene in overdose emergency situations. SIFs provide positive health benefits (reducing transmission of HIV and viral hepatitis, bacterial infections, and overdose mortality) without evidence for negative health or social consequences. SIFs serve most-at-risk persons, including those who inject in public or inject frequently, and those who do not use other public health programs. It is critical to address legal, ethical, and local concerns, develop and implement relevant policies and procedures, and assess individual- and community-level needs and benefits of SIFs given local epidemiologic data.

CONCLUSIONS

SIFs have the potential to reduce viral and bacterial infections and overdose mortality among those who engage in high-risk injection behaviors by offering unique public health services that are complementary to other interventions.

Expanded syringe exchange programs and reduced HIV infection among new injection drug users in Tallinn, Estonia

BACKGROUND

Estonia has experienced an HIV epidemic among intravenous drug users (IDUs) with the highest per capita HIV prevalence in Eastern Europe. We assessed the effects of expanded syringe exchange programs (SEP) in the capital city, Tallinn, which has an estimated 10,000 IDUs.

METHODS

SEP implementation was monitored with data from the Estonian National Institute for Health Development. Respondent driven sampling (RDS) interview surveys with HIV testing were conducted in Tallinn in 2005, 2007 and 2009 (involving 350, 350 and 327 IDUs respectively). HIV incidence among new injectors (those injecting for < = 3 years) was estimated by assuming (1) new injectors were HIV seronegative when they began injecting, and (2) HIV infection occurred at the midpoint between first injection and time of interview.

RESULTS

SEP increased from 230,000 syringes exchanged in 2005 to 440,000 in 2007 and 770,000 in 2009. In all three surveys, IDUs were predominantly male (80%), ethnic Russians (>80%), and young adults (mean ages 24 to 27 years). The proportion of new injectors decreased significantly over the years (from 21% in 2005 to 12% in 2009, p = 0.005). HIV prevalence among all respondents stabilized at slightly over 50% (54% in 2005, 55% in 2007, 51% in 2009), and decreased among new injectors (34% in 2005, 16% in 2009, p = 0.046). Estimated HIV incidence among new injectors decreased significantly from 18/100 person-years in 2005 and 21/100 person-years in 2007 to 9/100 person-years in 2009 (p = 0.026).

CONCLUSIONS

In Estonia, a transitional country, a decrease in the HIV prevalence among new injectors and in the numbers of people initiating injection drug use coincided with implementation of large-scale SEPs. Further reductions in HIV transmission among IDUs are still required. Provision of 70 or more syringes per IDU per year may be needed before significant reductions in HIV incidence occur.

Associations between herpes simplex virus type 2 and HCV With HIV among injecting drug users in New York City: the current importance of sexual transmission of HIV

OBJECTIVES

We examined relationships between herpes simplex virus type 2 (HSV-2), a biomarker for sexual risk, and HCV, a biomarker for injecting risk, with HIV among injecting drug users (IDUs) who began injecting after large-scale expansion of syringe exchange programs in New York City.

METHODS

We recruited 337 heroin and cocaine users who began injecting in 1995 or later from persons entering drug detoxification. We administered a structured interview covering drug use and HIV risk behavior and collected serum samples for HIV, HCV, and HSV-2 testing.

RESULTS

HIV prevalence was 8%, HSV-2 39%, and HCV 55%. We found a significant association between HSV-2 and HIV (odds ratio [OR] = 7.9; 95% confidence interval [CI] = 2.9, 21.4) and no association between HCV and HIV (OR = 1.14; 95% CI = 0.5, 2.6). Black IDUs had the highest prevalence of HSV-2 (76%) and HIV (24%) but the lowest prevalence of HCV (34%).

CONCLUSIONS

Most HIV infections among these IDUs occurred through sexual transmission. The relative importance of injecting versus sexual transmission of HIV may be critical for understanding racial/ethnic disparities in HIV infection.

Benefits of concurrent syringe exchange and substance abuse treatment participation

Participation in syringe exchange programs (SEPs) is associated with many individual and public health benefits but may have little impact on reducing drug use without concurrent treatment engagement. This study evaluated rates of drug use, other risk behaviors, and illegal activities in newly registered SEP participants (N = 240) enrolled versus not enrolled in substance abuse treatment over a 4-month observation window and examined the effect of days in treatment on these outcomes. After controlling for baseline differences, SEP registrants enrolled in treatment (n = 113) reported less days of opioid and cocaine use, injection drug use, illegal activities, and incarceration than those not enrolled in treatment (n = 127). For those enrolled in treatment, days of treatment was strongly correlated with each of these outcomes. These findings provide good evidence for a dose-response effect of treatment in syringe exchangers and suggest that substance abuse treatment significantly expands the harm reduction benefits of SEP participation.