There are approximately 16 million people who inject drugs (PWIDs) worldwide.1 Injection drug use (IDU) is associated with dire health consequences including death from overdose and increased risk for exposure to blood-borne infectious diseases such as HIV and hepatitis C virus (HCV).1 PWIDs may engage in risky behaviors, such as sharing injection equipment or exchange of sex for money or drugs, which increase their risk of infection and contributes to the global disease burden of IDU. Harm-reduction strategies aim to reduce high-risk behaviors among PWIDs and, hence, the consequences associated with IDU. Here, we review evidence for the efficacy of three widely implemented and well-validated harm-reduction strategies for PWIDs: (1) needle- and syringe-exchange programs, (2) medication-assisted treatment for opioid use disorder (OUD), (3) and HIV testing and counseling programs.
Needle and Syringe Programs
Needle and syringe programs (NSPs) aim to reduce high-risk injection practices, such as sharing or reusing injection equipment, by distributing free needles and syringes or by exchanging used equipment for new equipment.2,3 These programs facilitate the use of sterile needles and syringes, thereby reducing risk of HIV transmission and other blood-borne pathogens via used equipment.2,4,5 NSPs can be fixed (operating at consistent locations) or mobile (covering geographic areas through vans or direct deliveries).3 These programs typically offer additional services and referrals for treatment, including basic health care and screening and counseling for HIV and substance dependence.3 As such, they serve as a point of contact to engage PWIDs in treatment.2,4,5
There is strong evidence that NSPS are effective in reducing risky injection practices internationally,5,6 including in low- and middle-income communities.7 There has also been evidence of a reverse effect, insofar as risky injection practices rise in areas served by NSPs when those programs close.5 An estimated 60% reduction in risky injection practices worldwide has been attributed to NSPs.8 However, studies specifically examining the effects of NSPs on HIV transmission rates have produced mixed results; effectiveness may depend on the availability of additional therapies such as medication-assisted treatment for OUD or antiretroviral therapy.4,6 There has been no evidence for harmful effects of NSPs, such as increases in new PWIDs or lending of syringes, or decreased motivation for reducing drug use.5
The United States has been slower than other countries to adopt NSPs due to a widely held zero-tolerance attitude toward drug use.5 Bans preventing the allocation of federal funds to NSPs were in effect from 1988 to 2009 and 2011 to 2016,9,10 further restricting the implementation of these programs nationwide.3 As of 2013, there were 204 NSPs in the US, the majority (69%) of which were located in urban areas. Although these programs have demonstrated efficacy in reducing needle-sharing and injecting with used needles in cities such as Seattle11 and San Francisco,12 data on the effectiveness of NSPs in rural and suburban areas are needed.
Medication-Assisted Treatment for Opioid Use Disorder
Medication-assisted treatment (MAT) for OUD can reduce patients' withdrawal symptoms and cravings for opioids, thereby reducing the harms associated with intravenous drug use such as transmission of HCV and HIV.2 MAT doubles opioid abstinence rates among patients with OUD relative to psychosocial treatment alone.13 MAT may be broadly categorized into opioid agonist (methadone, buprenorphine, levo alpha acetyl methadol [LAAM]) and antagonist (naltrexone) therapies. LAAM was discontinued in Europe in 2001 and in the US in 2003 over concerns regarding severe cardiac adverse events.14 In all cases, MAT should be combined with psychosocial treatment focused on educating patients about addiction, enhancing motivation to change, building skills to cope with cravings to use, and preventing relapse.15
Opioid agonist medications reduce craving and withdrawal symptoms and block the rewarding effects of other opioids. Methadone is the most widely-used MAT for OUD,16 and multiple clinical trials have supported its effectiveness in reducing intravenous drug use, needle-sharing behavior, and illicit opioid use among this patient group.16,17 Furthermore, among patients with OUD, methadone therapy is associated with fewer reported sexual partners and exchanges of sex for drugs or money and lower rates of seroconversion from HIV negative to HIV positive relative to placebo.16 Like methadone, the partial opioid agonist buprenorphine (administered as monotherapy, or in conjunction with the opioid antagonist naloxone) is effective for reducing needle-sharing behavior among patients with OUD,18,19 improving treatment retention, and reducing opioid use; efficacy at doses ≥7 mg/day is similar to that of methadone.20 Treatment with either methadone or buprenorphine can also prevent the transmission of HCV among PWIDs, as evidenced by a recent study showing a 60% reduction in HCV infection among HCV-negative PWIDs, relative to no treatment.21
Naltrexone is an opioid antagonist used to prevent relapse among patients with OUD. It is available in oral- and long-acting injectable preparations. Although naltrexone can precipitate withdrawal in opioid-dependent patients, and thus should not be used prior to the completion of a medically supervised withdrawal protocol, it has no potential for abuse and no associated withdrawal syndrome, unlike methadone and buprenorphine. Oral naltrexone is best suited for patients who are highly motivated to remain abstinent from opioids, as compliance is poor and drop-out rates are high (up to 70%–80%).22 A meta-analysis study of 13 trials found no significant differences between oral naltrexone and placebo or no pharmacological treatment in terms of retention in treatment and abstinence from opioids, but results favor naltrexone over placebo when medication abstinence is strictly enforced.22 However, caution is warranted as there is evidence for increased risk for opioid overdose-related mortality in patients after discontinuation of oral naltrexone in clinical trials.13 Injectable extended-release naltrexone is approved in the US for treatment of OUD, but evidence for its efficacy is limited, and data on relative efficacy versus opioid agonist MAT are lacking at this time.13
HIV Testing and Counseling
HIV testing and counseling can be highly effective in reducing the spread of HIV among PWIDs, especially when testing is voluntary, accurate, and rapid (ie, results available in the same visit).23 Multiple studies have demonstrated that HIV testing and counseling are effective in reducing sexual risk behaviors and some injection risk behaviors among PWIDs,4,7,24 often through linkage to treatment, resources on safer sex and risk reduction, and other services.2,4,7 Community-based approaches, including those run by outreach workers, are especially successful at increasing access to HIV testing for PWIDs, who may be unlikely to return to other facilities for follow-up visits.2
The Centers for Disease Control and Prevention expanded routine HIV testing in 2004.25 A large survey of PWIDs in five cities, conducted between 1998 and 2002, showed that over 90% of PWIDs had been tested, representing approximately a 15% increase since the early 1990s.25 However, there were demographic differences in coverage, with men and Hispanics less likely to be tested, and participants in NSPs more likely.25 Despite promising declines in HIV transmission and increased testing among PWIDs, enhancement of services and expansion to vulnerable or marginalized populations are needed.26 For instance, one marginalized group of interest in HIV testing and counseling interventions is criminally involved PWIDs. Among criminally involved PWIDs in correctional institutions and in the community (ie, on probation), HIV education and risk assessment are associated with reduced sharing of injection drug equipment and drug use overall; immediate and regular HIV testing (eg, at intake or on-site at probation offices) is recommended for these people.27
HIV testing and counseling have demonstrated effective reduction of risk behaviors in countries across several continents where PWIDs face high HIV rates and barriers to testing and care.7 For example, the National Institute on Drug Abuse standardized HIV Counseling and Education Intervention Model was implemented in South China, where stigma and discrimination prevent many PWIDs from receiving treatment.24 The intervention was associated with significant reductions in injecting risk behaviors that endured over several months, even without individualized counseling. This study also showed significant improvement in HIV knowledge and condom use and demonstrated that relationships between PWIDs and counselors were important to reducing stigma and improving access to care.24
Barriers to Harm Reduction for People Who Inject Drugs
Despite the effectiveness of several harm-reduction methods, PWIDs are a vulnerable and marginalized population who face multiple barriers to treatment. PWIDs may be stigmatized as responsible for contracting HIV or other illnesses because of their drug use, resulting in sanctions such as corporal punishment and incarceration in some countries.9 Stigma may lead PWIDs to underutilize HIV prevention methods, such as testing and counseling.9
Treatment retention presents another challenge for harm-reduction services. For instance, discontinuation of methadone maintenance therapy is associated with relapse among patients with OUD.16 Furthermore, PWIDs are often linked to health care services through NSPs; therefore, discontinuing those services increases overall health risk. Psychosocial interventions such as cognitive-behavioral therapy and contingency management (ie, rewarding treatment compliance with small monetary incentives) can help retain PWIDs in treatment and prevent relapse.28,29
Women, youth, and racial/ethnic minorities face heightened risk and barriers to harm-reduction services compared with other PWIDs. The efficacy of harm-reduction strategies is less well-established among women and youth who inject drugs; they have lower rates of engagement in harm-reduction services and recruitment into intervention trials.9 Among women who inject drugs, a number of lifestyle factors may increase overall health risk, including abuse, homelessness, involvement in high-risk sex work, and psychiatric comorbidities; they may avoid wellness visits because they fear losing custody of their children should their drug use be disclosed.9,30 Such barriers can be addressed through women-only service centers, supervised waiting rooms for children, flexibility in frequency of visits, and integration or linkage to services such as sexual and reproductive health and women's shelters.30
Finally, across cultures, racial/ethnic minorities bear the brunt of health risks such as HIV.25 Education aimed to enhance providers' cultural competence may improve quality of interactions with minority PWIDs, which may facilitate greater trust in these communities.
Furthermore, structural changes are needed, including increased programming to target community-level risks (eg, disadvantage, violence, and drug distribution) and address health disparities.25
As reviewed above, NSPs, MAT for OUD, and HIV testing and counseling can mitigate the harmful consequences of IDU, especially when offered in conjunction with basic health care and other services. Additionally, there are other multiple well-validated harm-reduction strategies for reducing risk for HIV and other diseases, including antiretroviral therapy (ART) for HIV and condom distribution programs for PWIDs and their sexual partners.2 The three harm-reduction strategies reviewed in this article are widely implemented and well-validated among PWIDs worldwide. More research is needed on the effectiveness of other strategies among PWIDs, such as ART, which can effectively reduce risk of HIV transmission.22 In sum, NSPs, MAT for OUD, and HIV testing and counseling are effective harm-reduction interventions for PWIDs. Greater ease of access to such harm-reduction services would benefit public health overall—and especially for subpopulations of PWIDs (eg, women and ethnic minorities). Because of the severe consequences of undetected and untreated illness among PWIDs, additional research on overcoming barriers to treatment—and better means of “scaling up” pilot projects demonstrated to be effective—is needed to improve the health of this vulnerable population.
- Mathers BM, Degenhardt L, Phillips B, et al. Global epidemiology of injecting drug use and HIV among people who inject drugs: a systematic review. Lancet. 2008;372(9651):1733–1745. doi:10.1016/S0140-6736(08)61311-2 [CrossRef]
- WHO, UNODC, UNAIDS technical guide for countries to set targets for universal access to HIV prevention, treatment and care for injecting drug users – 2012 revision. http://www.who.int/hiv/pub/idu/targets_universal_access/en/. Accessed December 7, 2016.
- National Research Council (US)Institute of Medicine (US) Panel on Needle Exchange and Bleach Distribution Programs. Needle exchange and bleach distribution programs in the United States. https://www.ncbi.nlm.nih.gov/books/NBK232350/. Accessed December 7, 2016.
- Degenhardt L, Mathers B, Vickerman P, Rhodes T, Latkin C, Hickman M. Prevention of HIV infection for people who inject drugs: why individual, structural, and combination approaches are needed. Lancet. 2010;376(9737):285–301. doi:10.1016/S0140-6736(10)60742-8 [CrossRef]
- Wodak A, Cooney A. Do needle syringe programs reduce HIV infection among injecting drug users: a comprehensive review of the international evidence. Subst Use Misuse. 2006;41(6–7):777–813. doi:10.1080/10826080600669579 [CrossRef]
- Palmateer N, Kimber J, Hickman M, Hutchinson S, Rhodes T, Goldberg D. Evidence for the effectiveness of sterile injecting equipment provision in preventing hepatitis C and human immunodeficiency virus transmission among injecting drug users: a review of reviews. Addiction. 2010;105(5):844–859. doi:10.1111/j.1360-0443.2009.02888.x [CrossRef]
- Dutta A, Wirtz AL, Baral S, Beyrer C, Cleghorn FR. Key harm reduction interventions and their impact on the reduction of risky behavior and HIV incidence among people who inject drugs in low-income and middle-income countries. Curr Opin HIV AIDS. 2012;7(4):362–368. doi:10.1097/COH.0b013e328354a0b5 [CrossRef]
- The United States President's Emergency Plan for AIDS Relief. Comprehensive HIV Prevention for People Who Inject Drugs, Revised Guidance. https://www.pepfar.gov/documents/organization/144970.pdf. Accessed December 14, 2016.
- Strathdee SA, Shoptaw S, Dyer TP, Quan VM, Aramrattana ASubstance Use Scientific Committee of the HIV Prevention Trials Network. Towards combination HIV prevention for injection drug users: addressing addictophobia, apathy and inattention. Curr Opin HIV AIDS. 2012;7(4):320–325. doi:10.1097/COH.0b013e32835369ad [CrossRef]
- Ungar L. Funding ban on needle exchanges effectively lifted. http://www.usatoday.com/story/news/nation/2016/01/07/funding-ban-needle-exchanges-effectively-lifted/78420894/. Accessed December 7, 2016.
- Burt RD, Thiede H. Reduction in needle sharing among Seattle-area injection drug users across 4 surveys, 1994–2013. Am J Public Health. 2015;106(2):301–307. doi:10.2105/AJPH.2015.302959 [CrossRef]
- Kim NJ, Jin H, McFarland W, Raymond HF. Trends in sources and sharing of needles among people who inject drugs, San Francisco, 2005–2012. Int J Drug Policy. 2015;26(12):1238–1243. doi:10.1016/j.drugpo.2015.08.013 [CrossRef]
- Connery HS. Medication-assisted treatment of opioid use disorder: review of the evidence and future directions. Har Rev Psychiatry. 2015;23(2):63–75. doi:10.1097/HRP.0000000000000075 [CrossRef]
- US Food and Drug Administration. Safety. Orlaam (levomethadyl acetate hydrochloride). http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm153332.htm. Accessed December 8, 2016.
- Substance Abuse and Mental Health Services Administration. Medication-assisted treatment for opioid addiction in opioid treatment programs. http://store.samhsa.gov/shin/content//SMA12-4214/SMA12-4214.pdf. Accessed December 14, 2016.
- Gowing L, Farrell MF, Bornemann R, Sullivan LE, Ali R. Oral substitution treatment of injecting opioid users for prevention of HIV infection. Cochrane Database Syst Rev. 2011;8: CD004145. doi:10.1002/14651858.CD004145.pub4 [CrossRef].
- Mattick RP, Breen C, Kimber J, Davoli M. Methadone maintenance therapy versus no opioid replacement therapy for opioid dependence. Cochrane Database Syst Rev. 2003; 2:CD002209.
- Edelman EJ, Chantarat T, Caffrey S, et al. The impact of buprenorphine/naloxone treatment on HIV risk behaviors among HIV-infected, opioid-dependent patients. Drug Alcohol Depend. 2014;139:79–85. doi:10.1016/j.drugalcdep.2014.03.006 [CrossRef]
- Otiashvili D, Piralishvili G, Sikharulidze Z, Kamkamidze G, Poole S, Woody GE. Methadone and buprenorphine-naloxone are effective in reducing illicit buprenorphine and other opioid use, and reducing HIV risk behavior--outcomes of a randomized trial. Drug Alcohol Depend. 2013;133(2):376–382. doi:10.1016/j.drugalcdep.2013.06.024 [CrossRef]
- Mattick RP, Breen C, Kimber J, Davoli M. Buprenorphine maintenance versus placebo or methadone maintenance for opioid dependence. Cochrane Database Syst Rev. 2014;2: CD002207. doi:10.1002/14651858.CD002207.pub4 [CrossRef].
- Tsui JI, Evans JL, Lum PJ, Hahn JA, Page K. Association of opioid agonist therapy with lower incidence of hepatitis c virus infection in young adult injection drug users. JAMA Internal Med. 2014;174(12):1974–1981. doi:10.1001/jamainternmed.2014.5416 [CrossRef]
- Minozzi S, Amato L, Vecchi S, Davoli M, Kirchmayer U, Verster A. Oral naltrexone maintenance treatment for opioid dependence. Cochrane Database Syst Rev. 2011;4:CD001333. doi:10.1002/14651858.CD001333.pub4 [CrossRef].
- Centers for Disease Control and Prevention (CDC). HIV diagnoses among injection-drug users in states with HIV surveillance--25 states, 1994–2000. MMWR Morb Mortal Wkly Rep. 2003;52(27):634–636.
- Chen HT, Liang S, Liao Q, et al. HIV voluntary counseling and testing among injection drug users in south China: a study of a non-government organization based program. AIDS Behav. 2007;11(5):778–788. doi:10.1007/s10461-007-9215-x [CrossRef]
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