Authors: Dita Broz, Neal Carnes, Johanna Chapin-Bardales, Don C. Des Jarlais, Senad Handanagic, Christopher M. Jones, R. Paul McClung, Alice K. Asher
Categories: Article
Source: American journal of preventive medicine
Diagnoses of HIV among people who inject drugs have increased in the U.S. during 2014–2018 for the first time in 2 decades, and multiple HIV outbreaks have been detected among people who inject drugs since 2015. These epidemiologic trends pose a significant concern for achieving goals of the federal initiative for Ending the HIV Epidemic in the U.S. Syringe services programs are cost effective, safe, and highly effective in reducing HIV transmission and are an essential component of a comprehensive, integrated approach to addressing these concerns. Yet, geographic coverage of these programs remains limited in the U.S., and many jurisdictions continue to have laws and policies that limit or disallow syringe services programs. An in-depth literature review was conducted on the role of syringe services programs in the Ending the HIV Epidemic initiative. Empirical and model-based evidence consistently shows that syringe services programs have the highest impact in HIV prevention when combined with access to medications for substance use disorder and antiretroviral therapy. Their effectiveness is further maximized when they provide services without restrictions and include proven and innovative strategies to expand access to harm-reduction and clinical services (e.g., peer outreach, telehealth). Increasing geographic and service coverage of syringe services programs requires strong and sustainable policy, funding, and community support and will need to address new challenges related to the COVID-19 pandemic. Syringe services programs have a key role in all 4 Ending the HIV Epidemic initiative strategies—Prevent, Diagnose, Treat, and Respond—and thus are instrumental to its success in preventing disease and saving lives.
Sharing syringes and other injection equipment during injection drug use (IDU) continues to be an important route of HIV transmission in the U.S. and worldwide.^1–3^ In the U.S., diagnoses of HIV infection attributed to IDU were steadily declining for decades,^3,4^ owing in large part to effective HIV prevention interventions for people who inject drugs (PWID), including syringe services programs (SSPs) that provide access to sterile injection equipment and other health and social services.^5^ HIV diagnoses among PWID increased, however, during 2014–2018, and multiple HIV outbreaks have been detected since 2015.^3,6,7^ These epidemiologic trends suggest increases in HIV transmission related to IDU that pose a significant concern for achieving goals of the federal initiative Ending the HIV Epidemic (EHE) in the U.S.^8^
Over the past 2 decades, unprecedented increases in opioid use in the U.S. have led to increased prevalence of IDU^9–12^ and injection-related health and social consequences that may further complicate HIV prevention.^13^ For instance, the rates of acute hepatitis C virus (HCV) cases increased 71% between 2014 and 2018, indicating increases in unsafe injection practices that could also lead to HIV transmission.^14^ The 2015 HIV outbreak among PWID in a nonurban area of Indiana was predated by widespread HCV transmission^15^ and highlighted the devastating impact of IDU in communities that have previously lacked effective, evidence-based public health interventions, including SSPs.^16–18^ The multiple HIV outbreaks across the U.S. among PWID since then further demonstrate the challenges in HIV prevention and care in the context of ongoing syndemics of drug use, overdose, and infectious diseases.^7^
Research over the past 3 decades has provided compelling evidence on the effectiveness, safety, and cost effectiveness of SSPs in preventing HIV infection among PWID.^19–23^ SSPs also play a key role in reducing additional health sequelae of IDU, such as viral hepatitis, life-threatening bacterial and fungal infections, and overdose deaths,^24,25^ and provide other public health benefits, including safe disposal of used syringes^26^ and linkage to substance use disorder (SUD) treatment.^27,28^ SSPs also can contribute to interventions for preventing drug injection initiation.^29^ Importantly, SSPs have not been shown to increase drug use or crime.^30–32^ Despite this overwhelming evidence, coverage of SSPs remains limited in the U.S.^33,34^ and many jurisdictions continue to have laws and policies that limit or disallow SSP services.^35,36^ The coronavirus disease 2019 (COVID-19) crisis has further exacerbated challenges in obtaining these lifesaving services,^37,38^ compromising efforts to end HIV among PWID if not successfully addressed.
The EHE initiative aims to reduce new HIV infections in the U.S. by 90% by 2030.^8,39^ EHE leverages critical scientific advances in HIV prevention and treatment and provides new resources to jurisdictions most heavily impacted. The initiative scales up 4 science-based Prevent, Diagnose, Treat, and Respond. This special article summarizes findings from an in-depth review of available evidence on the role of SSPs in EHE.
The in-depth literature review occurred in 2 stages. First, a search was conducted on December 8, 2020 in PubMed, Embase, Scopus, Cochrane, and CINAHL databases and included keywords to describe SSPs and their effectiveness, SSPs in the context of each of the 4 EHE strategies (i.e., Prevent, Diagnose, Treat, and Respond), and SSPs’ operational successes and challenges. Results were limited to articles in English, published in peer-reviewed, professional publications. Given the breadth of scientific evidence, this review focused on studies published since the 2004 WHO comprehensive literature review.^40^ Publications before 2004 were included for historical reference or if more recent publications were not available. Second, additional reviews of documents not identified in the first search were conducted, which included materials disseminated through the Centers for Disease Control and Prevention (CDC) website (e.g., factsheets), additional papers referenced by publications identified in the first review, and papers published during the writing of this manuscript after December 8, 2020.
The first SSPs were established in the U.S. in the late 1980s in response to the HIV epidemic. Since then, many studies in the U.S. and internationally have demonstrated SSP safety and effectiveness in reducing HIV transmission, and in 2004, WHO declared the provision of sterile injection equipment to PWID an essential component for HIV prevention programs.^41^ In December 2020, the North American Syringe Exchange Network directory listed 494 SSPs operating in 44 states and Puerto Rico.^42^
Provision of sterile syringes and safe disposal of used syringes are fundamental services of all SSPs. Many SSPs offer additional services for preventing HIV transmission and other health and social sequelae of drug use.^43,44^ Programs are located in all regions of the country,^42,45^ and although most are fixed sites, some operate mobile sites, on-demand/on-call services, street outreach, and delivery to increase access.^46,47^ To further expand syringe distribution to areas where SSP implementation is limited or not feasible, pharmacies, hospitals, mail delivery, and vending machines can provide important complementary services to SSPs (Box 1^48–56^).^57^ The philosophical underpinning of all SSPs is harm reduction and creating a safe space for people who use drugs to receive needed, targeted services without fear of judgment or punishment.
The effectiveness of SSPs in reducing injection risk behaviors and HIV transmission has been well studied, with research dating back to 1989.^20,40^ Early studies found that if SSPs are implemented when HIV prevalence is <5% among PWID, on a large scale, and with trust-building communication with PWID, SSPs can reduce and maintain HIV transmission at low levels.^58^ An HIV incidence study in New York City in 1992–2002 found that, if implemented on a large scale during ongoing high HIV prevalence (>40%) among PWID, SSPs can lead to large reductions in HIV incidence and eventual public health control of HIV transmission among PWID.^59^ A recent meta-analysis of SSP effectiveness that included studies from North America and Europe estimated a 58% reduction in HIV among PWID attending SSPs compared with PWID who did not.^20^
The effectiveness of SSPs in preventing HIV depends, in part, on their ability to follow evidence-based best practices for services delivery.^44^ A key best practice is ensuring needs-based syringe distribution; that is, providing access to sterile syringes based on client needs and without restrictions as part of low-threshold service provision. Difficulty in accessing sterile injection equipment is associated with increased syringe sharing and reuse,^60,61^ whereas sufficient access can significantly decrease syringe sharing.^62,63^ When PWID are able to use a sterile syringe for each injection, HIV transmission can be reduced by almost 60%.^20^ A survey of clients from 24 SSPs found that 61% of PWID who attended SSPs with needs-based syringe distribution policies obtained a sterile syringe for each reported injection compared with 26% of PWID accessing SSPs with a limited 1-for-1 syringe distribution policy (i.e., 1 sterile syringe is exchanged for 1 used syringe).^64^ Concerns that increasing access to syringes may increase the number of improperly discarded syringes in a community have not been substantiated by available evidence.^65^ Although any sharp litter that can cause injury is a concern, HIV transmission following community-acquired needlestick injury is extremely unlikely and no cases have been reported to date.^66^ Building on decades of research, CDC recommends needs-based syringe distribution for SSPs to ensure a new, sterile syringe for each injection.^67^ A needs-based syringe distribution model also recognizes the essential role of peers, including current clients of SSPs, as syringe distributors and risk reduction educators.^68^ Peer distributors have been found to reach more diverse networks of PWID and those facing barriers to accessing SSPs (e.g., houselessness, lack of transportation).^69^ Despite this, majority of the SSPs operate under policies that restrict the number of syringes provided, which often also impacts the capacity to support peer distribution.^45^
Additional best practices focus on ensuring low-threshold access to all other SSP services, strong community partnerships, and program sustainability. Table 1 summarizes recommendations from a 2009 expert consultation meeting for maximizing SSP effectiveness^70^ and a 2020 CDC technical package for SSPs.^71^
Although SSPs are effective in reducing HIV risk among PWID through sterile syringe access without ancillary services readily available,^72,73^ empirical evidence and model-based projections consistently show that SSPs have the highest impact in HIV prevention when a comprehensive, integrated approach is implemented.^44,57^ This holistic prevention and care approach addresses the myriad health and social sequelae of IDU that also impact HIV prevention. The combination of services, in addition to needs-based syringe access, includes at access to HIV and HCV testing and linkage to care; SUD treatment, including medications for opioid use disorder (MOUD); and naloxone distribution.^71^
Diagnosing people with HIV as early as possible is key to rapid initiation of treatment and viral suppression; nevertheless, only 55% of PWID received HIV testing in the past year per CDC recommendations.^74^ Because SSPs often reach PWID who may not otherwise engage with the healthcare system, SSPs are an important source of regular HIV testing. In a survey of PWID conducted across 23 SSPs, 44% reported a primary care visit in the past 6 months, but 78% had ≥2 SSP visits in the past 30 days.^75^ In a study of administrators from 127 SSPs, 87% reported providing on-site HIV testing.^76^ This is in contrast to other settings frequented by PWID, including SUD treatment facilities, of which only 23%–40% report offering any testing,^77^ and emergency departments, where <1% of visits overall include HIV testing.^78^
When HIV testing is offered at SSPs, uptake can be high. One SSP in Miami found a 42% increase in HIV and HCV testing when they offered both tests to all clients at intake and monthly thereafter.^79^ A meta-analysis found that PWID accessing SSPs were 1.6 times more likely to have had an HIV test in the past year.^80^ Nevertheless, key barriers to HIV testing exist and may impact uptake at SSPs. A study of 127 SSPs found that although a large proportion of SSPs offered HIV testing, an average of 15%–17% of clients tested on-site.^76^ The authors noted potential financial and organizational capacity barriers, in addition to client-related barriers, to testing. The EHE scale-up efforts coupled with new resources provide an important opportunity to expand HIV testing for PWID through increasing the geographic coverage of SSPs and by supporting improvements in SSPs’ capacity to provide regular HIV testing services and linkage to care. Such efforts need to include strategies to address barriers previously found to be associated with low uptake of HIV testing, including housing instability, stigma around drug use, social isolation, and inadequate transportation.^81,82^
Improving access and use of HIV pre-exposure prophylaxis (PrEP) by people without HIV and antiretroviral therapy (ART) for people with HIV to achieve viral suppression is key to HIV prevention. These biomedical interventions also address sexual transmission among PWID. Other interventions, such as SUD treatment, can reduce IDU and thereby lower injection transmission risk and improve adherence of both PrEP and ART medications.
SSPs can have an important role in connecting PWID with these interventions. PWID face significant individual and structural barriers to accessing clinical HIV prevention and care services, including out-of-pocket medical costs, lack of health insurance, lack of transportation, housing instability, negative healthcare experiences, and low provider willingness to prescribe HIV medications amidst concerns about adherence, in addition to the many competing priorities related to drug use.^83–89^ However, because SSPs can offer a comprehensive, integrated approach for harm reduction, they are well situated to assist PWID in overcoming these barriers and provide or facilitate linkage to client-centered prevention and care services to achieve EHE goals. Implementation research is critical to addressing how to effectively and efficiently integrate these services in SSPs.^90^
Daily oral emtricitabine and tenofovir as PrEP can reduce the risk of HIV infection among PWID by 49%, with even higher efficacy (74%) given sufficient adherence.^91^ Nevertheless, awareness and use of PrEP among PWID remain low.^74,92–94^ Among those aware, interest in using oral daily PrEP has been around 60% in studies of urban and rural PWID,^92–96^ but only 1%–4% of PWID have reported using PrEP.^74,92,93,97^ PWID attending SSPs report greater awareness of PrEP, suggesting that SSPs provide an effective avenue for increasing PrEP awareness and utilization.^83–85,98^ Several studies have found that PWID prefer accessing PrEP at SSPs where there may be less stigma and greater comfort, and colocation could reduce the burden of additional clinical visits.^83–86,89^ Providers also prefer service colocation, which could include placing PrEP providers within an SSP or allowing standing PrEP orders for PWID at SSPs.^73,99^
Evidence-based program models for successful PrEP implementation within SSPs remain sorely needed. Two studies found that although most PWID accessing SSPs expressed interest in using PrEP, none initiated PrEP.^96,100^ In a study of women who inject drugs, more than two thirds initiated PrEP, although of these, only about a third remained on PrEP at Week 24 and daily adherence was low.^101^ These findings suggest that SSPs offering PrEP need support to help identify and address barriers to PrEP uptake and adherence among their clients. Further, SSPs may need to develop options for direct provision or facilitating direct provision of PrEP, possibly via telehealth providers, to support low-barrier access and timely PrEP initiation.
SSPs serve an important role in diagnosing, linking, and navigating PWID to HIV care, supporting them along the continuum of care to achieve viral suppression, and thus contribute to preventing ongoing HIV transmission and improving health outcomes.^87,102–104^ In 2015, approximately a quarter of the 127 surveyed SSP administrators indicated that their programs offered HIV viral load testing or HIV treatment.^76^ In Kentucky, North Carolina, and West Virginia, a region hard hit by the opioid crisis and of particular concern for HIV outbreaks, a recent study found that most SSPs in these states linked their clients to HIV care services, thus suggesting feasibility of these clinical services in both urban and rural SSPs.^105^ Modeling studies demonstrate a significant impact of SSPs when combined with ART,^44^ and SSPs can provide strategies, such as telehealth, directly administered ART, and on-site medical lockers to store ART for SSP clients, to further support ART use and adherence.^87,106^ HIV care and navigation services at SSPs can be tailored to meet the unique needs of PWID subpopulations, such as pregnant women, women who engage in sex work, young PWID, and trans PWID, within a trusted, judgment-free setting.^88,107^
Treatment for SUD, including MOUD, is a key health service that can reduce or stop IDU, thus lowering HIV transmission risk.^108–111^ Modeling studies demonstrate strong, cumulative effects when SSPs and access to MOUD are offered, reducing the risk of HIV transmission by nearly 50%.^44^ Furthermore, research has consistently shown that comprehensive SSPs with MOUD and ART assist PWID to increase ART adherence, and this may also have implications for PrEP use and adherence.^44,88^ When referrals and patient navigation for SUD are offered, SSP clients are more likely to enter and remain in SUD treatment and stop injecting drugs than PWID who do not use SSPs.^27,112^ MOUD without additional interventions (e.g., psychosocial or behavioral therapy) has been found to be an effective treatment for SUD^113^; thus, access to MOUD that is low-threshold, client-centered, and affordable is essential. COVID-19–related temporary policy changes to federal guidance for MOUD treatment providers that allow telehealth to substitute in-person visits and increased number of doses patients bring home are positive improvements and should become permanent.^114^ Telehealth capacity in SSPs could greatly improve access to health services; an SSP in Miami recently implemented a free telehealth system to help clients initiate MOUD,^115^ which could provide a framework for expanding access to other clinical services, including PrEP and ART.
Effective HIV outbreak response requires health departments and their communities to establish partnerships and processes to identify rapid HIV transmission and respond swiftly by delivering HIV prevention and care services.^116^ In recent years, multiple HIV outbreaks in the U.S. have affected PWID.^7,16^ Without exception, SSPs have been crucial to the success of these outbreak responses. SSPs can support early detection of HIV transmission through routine HIV testing and retesting. By developing trusting relationships with PWID, SSP staff are also well positioned to identify shifts in drug use or injection behaviors that might signal increased concern for HIV risk.
When an outbreak is detected, SSPs provide valuable infrastructure for rapid delivery of essential prevention and care services, including expanded HIV testing, increased delivery of sterile injection equipment, linkage to care for HIV and SUD, PrEP, and delivery of health messages via peer networks or peer-education interventions.^117,118^ To rapidly identify service needs and barriers, SSPs can also facilitate qualitative interviews, quantitative surveys, or other rapid assessments; these investigation activities have been essential in identifying drivers of transmission in prior responses.^119,120^ Mobile SSPs can provide flexibility for directing services to new areas affected by an outbreak and for reaching community members unable to access fixed sites. Integration of SUD treatment, ART, and PrEP into SSP operations can be especially valuable during an outbreak, and close collaboration among SSPs, healthcare facilities, and health department staff (including disease intervention specialists) can promote a timely, well-coordinated, and culturally competent response.
Proactive implementation of an SSP before an outbreak occurs is vital for reducing an outbreak’s size and scope when compared with reactive implementation or the absence of SSPs.^17^ SSP implementation during an outbreak among PWID is possible, however, and should be prioritized early in the response. Of note, many recent U.S. outbreaks occurred in communities with an established SSP,^7^ indicating the importance of ongoing monitoring of changes in drug use patterns that may increase HIV transmission risk and identifying potential gaps in SSP services that can limit SSP effectiveness. Such gaps must be addressed with urgency during a response to interrupt HIV transmission. In prior outbreaks, identification of these gaps has led to new investments in services for PWID during and after the outbreak, including expansion or establishment of new SSPs, expansion of HIV testing, and hiring new staff to support future response efforts.^16,120–122^
Despite strong evidence demonstrating their public health benefits, SSPs remain limited in number, scale, scope, and reach in the U.S. owing to persistent legal, sociopolitical, and funding challenges.^5,35,123–126^ These issues, in particular longstanding federal funding prohibitions or restrictions, have led to an inefficient and uneven patchwork of laws, regulations, and policies related to SSPs. Moreover, some states maintain laws that criminalize possession of syringes, needles, and other injection equipment as well as directly prohibit the implementation of SSPs.^123,124,127^ Although increasing rates of overdose and infectious disease transmission among PWID have caused some states to enact SSP-supportive laws or policies,^128–130^ SSP implementation has not been commensurate with need^131,132^; some SSPs implemented after the 2015 HIV outbreak in Indiana were closed,^126,133^ and challenges related to laws and policies, funding, and community acceptance remain.
As of August 2019, a total of 32 states had laws that explicitly authorized SSPs and 39 states had taken steps to address legal concerns related to SSPs. However, in many of these states, inconsistencies and limitations among the laws persist, such as having laws that authorize distribution of syringes and others making possession of syringes illegal, or laws that required local governments or public safety to approve or be consulted before an SSP could be implemented. Furthermore, 12 states still provide no legal basis for SSP operation; these include 4 of the 7 EHE states designated as having a substantial number of HIV diagnoses in rural areas, and many are located in the U.S. South where HIV burden is high.^129,134,135^ Recent research found that among a geographically diverse sample of urban and rural SSPs, program administrators depicted many legal and policy challenges that limit SSPs. Many described operating in an ambiguous legal environment, and some underground or without explicit legal protection at the state or local level. Even in states with laws explicitly authorizing SSPs, they faced a complex and challenging process to receive local approval or attain community buy-in to implement or expand SSPs.^35^
Funding for SSPs has improved in recent years owing to the partial lifting of the ban on use of federal funds to support SSP services through the Consolidated Appropriations Act of 2016^136^; however, the ban on using these funds to purchase syringes has been a key challenge for SSPs.^35^ In addition, before these federal funds can be used, jurisdictions must provide evidence to CDC and receive a Determination of Need (DON) that they are experiencing or are at risk for significant increases in viral hepatitis or HIV infections owing to IDU.^136^ Currently, 6 states have not requested a DON.^137^ Importantly, after receiving a DON, jurisdictions and SSPs are still faced with having limited dedicated federal funding programs for SSPs. Emblematic of SSP funding challenges are the limited number of locations, days, and hours SSPs are able to operate.^138^ In 1 study, nearly 45% of SSPs were open 1 day per week and 41% were open ≤3 hours on the days they were open.^35^ The American Rescue Plan Act of 2021, which became law during the writing of the manuscript, directed resources to the Substance Abuse and Mental Health Services Administration that allows for support of SSPs and other harm-reduction services in the U.S.^139^ Guidance for implementing these funds is still in development.
Community acceptance and stigma are chronic problems facing SSPs and are inextricably linked to the persistent legal, policy, and funding challenges.^35,126,140^ A recent survey of U.S. adults found that 39% supported legalization of SSPs in their communities, and this varied significantly across political and socio-demographic characteristics. In addition, individuals who held greater stigma toward people who use opioids were 51% less likely to support legalization of SSPs, underscoring the import role stigma plays in support for SSPs.^141^
The COVID-19 pandemic significantly disrupted provision of SSP services and may compromise EHE efforts. As of April 2020, of 173 surveyed SSPs, 43% surveyed reported decreased availability of services, including in-person provision of injecting equipment or naloxone, HIV or HCV testing, and referrals to SUD treatment, and 25% closed ≥1 location.^37^ In another study of 65 SSPs, 15% discontinued all their services, and 25% have switched fully to mobile provision.^142^ Only 26% of SSPs continued to provide HIV or HCV testing, and most discontinued the provision of other medical services for clients.
The legal, sociopolitical, and funding challenges SSPs face result in missed opportunities to implement or expand comprehensive SSPs and limit their public health impact. The COVID-19 pandemic is further exacerbating existing barriers to SSP services and expanding inequity. If not addressed, these challenges stand to limit progress of the EHE initiative. Actions that can be taken to address these challenges are listed in Table 2.
Ending the HIV epidemic among PWID is achievable. We understand how HIV is transmitted among PWID and we have highly effective behavioral and biomedical interventions to substantially reduce risk and get close to 0 new HIV infections. SSPs are highly effective, cost effective, and safe in reducing HIV transmission in the communities where they operate. Their impact is maximized when they can follow best practices (e.g., needs-based access to sterile syringes) and are combined with access to MOUD, PrEP, and ART. SSPs have a key role in all 4 EHE strategies—Prevent, Diagnose, Treat, and Respond—and thus are instrumental to the success of EHE efforts. Nevertheless, coverage of these programs remains low in the U.S., and the COVID-19 crisis is further exacerbating existing challenges SSPs face. Increasing geographic and service coverage of SSPs will require strong and sustainable policy, funding, and community support to build on the successes of these programs and to drive innovation to prevent disease and save lives. Implementation research will be critical to informing these expansion efforts. With the EHE initiative, we have an opportunity of a lifetime to eliminate HIV among PWID and we have an ethical obligation to deliver the necessary programs at the scale required.
The authors would like to thank Jack F. Colbert, Librarian from the Stephen B. Thacker Centers for Disease Control and Prevention Library, for his assistance with generating the initial literature review and reference library. The authors also thank Dawn Smith and Andrew Margolis for reviewing an early version of the manuscript and providing valuable input.
All authors, other than DCDJ, were employees of the Centers of Disease Control and Prevention.
The authors alone made decisions about the scientific review design and interpretation of findings, writing the report, and the decision to submit the report for publication.
No financial disclosures were reported by the authors of this paper.