Peter J. Davidson’s research while affiliated with University of California, San Diego and other places

Background Oral Pre-exposure prophylaxis (PrEP) is effective in preventing HIV transmission. However, despite high rates of HIV risk behaviors among people who inject drugs (PWID), this population remains underserved by current HIV prevention efforts in the United States. To address this challenge, we conducted an in-depth exploration of perspectives on using oral PrEP among PWID engaged in the HIV Prevention Trials Network (HPTN) 094 INTEGRA Study. Methods Guided by the Practical, Robust, Implementation, and Sustainability Model (PRISM), our qualitative study drew on semi-structured interviews conducted as part of the embedded implementation science evaluation of HPTN 094 INTEGRA. Seventy-seven PWID participants from five sites across New York City, Houston, Los Angeles, Philadelphia, and Washington DC were interviewed to assess intervention delivery, care access, and engagement sustainability. Audio files were transcribed verbatim and analyzed via an inductive and deductive thematic approach. Results Most participants ( n = 46, 59.7%) discussed oral PrEP during their interview, though not directly prompted. Participants discussing PrEP had a mean age of 41.6 years and were predominantly white (54.3%) and cisgender men (60.9%). Among these, 15 participants described using PrEP. All participants had facilitated access to oral PrEP. Yet, the choice to use PrEP was influenced by personal risk perceptions, (mis)information about PrEP, and external factors (i.e. housing, financial security), which, for some, limited the autonomy to use PrEP. Two key themes emerged among participants using PrEP: ease of access and perceptions of high HIV risk. Those not using PrEP described two themes: low risk perception and prioritizing more urgent needs. Among participants not using PrEP a subgroup commonly described ambivalent interest, PrEP knowledge gaps, and PrEP readiness (i.e., contemplation). Conclusions Qualitative findings highlight that facilitated PrEP access was insufficient to motivate use for many participants. Rather, PrEP decision-making process (i.e., choice) was linked to risk perception and individuals’ capability to leverage PrEP as a resource based on their circumstances (i.e., autonomy). Participants’ descriptions of the centrality of choice and autonomy for PrEP use underscore that ease of access is a necessary pre-condition, but person-centered interventions should also address housing, financial stability, and urgent medical conditions to promote PrEP utilization among PWID. Clinical trial registration NCT04804027.

Background: Accessing opioid use disorder (OUD) treatment is difficult for individuals in unstable housing. This population often uses public libraries for computer and internet access, which could provide telehealth access to OUD treatment. Therefore, we developed a novel 12-week library-facilitated telehealth intervention study called "Bupe by the Book" (BBB), which uses library resources to facilitate the initiation and retention of OUD treatment with buprenorphine. Methods: This study involved a partnership between the San Diego Public Library and a federally qualified healthcare center attached to a homeless shelter (Father Joe's Villages (FJV) Village Health Center). We codesigned a pilot randomized controlled trial to evaluate a library-facilitated telehealth intervention in San Diego, California. We evaluated the intervention for its feasibility and acceptability and to obtain an estimate of the effect of the intervention on buprenorphine treatment outcomes. Individuals reporting homelessness and OUD (with or without other substance use) were eligible. Forty library patrons were recruited via flyers, screened for eligibility, and referred to the FJV Health Center for initial buprenorphine treatment intake visits. Participants who completed intake were enrolled and randomized to the library-facilitated telehealth condition, which involved the use of library internet and computer resources for follow-up visits to the clinic for buprenorphine treatment. The participants completed treatment follow-up in person or by phone in the control condition. Planned analyses (not powered to assess efficacy) will provide effect size estimates of the library-facilitated telehealth intervention on 1) buprenorphine use (measured in weekly urine drug screenings), 2) use of illicitly manufactured fentanyl (IMF) and other opioids (measured in weekly urine drug screens), 3) number of buprenorphine prescription pick-ups, 4) number and frequency of clinic visits, and 5) self-reported substance use, mental health, and quality of life measures at 1, 2, 4, 8, and 12 weeks. Discussion: The findings from this pilot study may support the adoption of library-facilitated telehealth treatment as a feasible and acceptable strategy to engage and retain unstably housed people with OUD in buprenorphine treatment. The lessons from this pilot study include the importance of community‒academic partnerships in sustainably adapting interventions in community-based settings. Trial registration: This trial was registered prospectively at ClinicalTrials.gov (registration number NCT05872386) on May 24, 2023.

Background: Supervised consumption sites (SCS) have been shown to reduce receptive syringe sharing among people who inject drugs (PWID) in the United States and elsewhere, which can prevent HIV and hepatitis C virus (HCV) transmission. PWID are at risk of disease transmission and may benefit from SCS, however legislation has yet to support their implementation. This study aims to determine the potential impact of SCS implementation on HIV and HCV incidence among PWID in three California counties. Methods: A dynamic HIV and HCV joint transmission model among PWID (sexual and injecting transmission of HIV, injecting transmission of HCV) was calibrated to epidemiological data for three counties: San Francisco, Los Angeles, and San Diego. The model incorporated HIV and HCV disease stages and HIV and HCV treatment. Based on United States data, we assumed access to SCS reduced receptive syringe sharing by a relative risk of 0.17 (95 % CI: 0.04-1.03). This model examined scaling-up SCS coverage from 0 % to 20 % of the PWID population within the respective counties and assessed its impact on HIV and HCV incidence rates after 10 years. Results: By increasing SCS from 0 % to 20 % coverage among PWID, 21.8 % (95 % CI: − 1.2-32.9 %) of new HIV infections and 28.3 % (95 % CI: − 2.0-34.5 %) of new HCV infections among PWID in San Francisco County, 17.7 % (95 % CI: − 1.0-30.8 %) of new HIV infections and 29.8 % (95 % CI: − 2.1-36.1 %) of new HCV infections in Los Angeles County, and 32.1 % (95 % CI: − 2.8-41.5 %) of new HIV infections and 24.3 % (95 % CI: − 1.6-29.0 %) of new HCV infections in San Diego County could be prevented over ten years. Conclusion: Our models suggest that SCS is an important intervention to enable HCV elimination and could help end the HIV epidemic among PWID in California. It could also have additional benefits such facilitating pathways into drug treatment programs and preventing fatal overdose.

Safe injection self-efficacy (SISE) is negatively associated with injection risk behaviors among people who inject drugs (PWID) but has not been examined in differing risk environments. We compared responses to a validated SISE scale between PWID in San Diego, California and Tijuana, Mexico, and examine correlates of SISE among PWID in Tijuana. PWID were recruited via street outreach for a longitudinal cohort study from October 2020–September 2021. We compared SISE scale items by city. Due to low variability in SISE scores among San Diego residents, we restricted analysis of factors associated with SISE to Tijuana residents and identified correlates of SISE score levels (low, medium, high) using ordinal logistic regression. Of 474 participants, most were male (74%), Latinx (78%) and Tijuana residents (73%). Mean age was 44. Mean SISE scores among San Diego residents were high (3.46 of 4 maximum) relative to Tijuana residents (mean: 1.93). Among Tijuana residents, White race and having previously resided in San Diego were associated with higher SISE scores. HCV and HIV seropositivity, homelessness, fentanyl use, polysubstance co-injection, and greater injection frequency were associated with lower SISE scores. We found profound inequalities between Tijuana and San Diego SISE, likely attributable to differential risk environments. Associations with fentanyl and polysubstance co-injection, injection frequency, and both HIV and HCV seropositivity suggest that SISE contribute to blood-borne infection transmission risks in Tijuana. SISE reflects an actionable intervention target to reduce injection risk behaviors, but structural interventions are required to change the risk environment.

Background HIV burden in the US among people who inject drugs (PWID) is driven by overlapping syndemic factors such as co-occurring health needs and environmental factors that synergize to produce worse health outcomes among PWID. This includes stigma, poverty, and limited healthcare access (e.g. medication to treat/prevent HIV and for opioid use disorder [MOUD]). Health services to address these complex needs, when they exist, are rarely located in proximity to each other or to the PWID who need them. Given the shifting drug use landscapes and geographic heterogeneity in the US, we evaluate a data-driven approach to guide the delivery of such services to PWID in local communities. Methods We used a hybrid, type I, embedded, mixed method, data-driven approach to identify and characterize viable implementation neighborhoods for the HPTN 094 complex intervention, delivering integrated MOUD and HIV treatment/prevention through a mobile unit to PWID across five US cities. Applying the PRISM framework, we triangulated geographic and observational pre-implementation phase data (epidemiological overdose and HIV surveillance data) with two years of implementation phase data (weekly ecological assessments, study protocol meetings) to characterize environmental factors that affected the viability of implementation neighborhoods over time and across diverse settings. Results Neighborhood-level drug use and geographic diversity alongside shifting socio-political factors (policing, surveillance, gentrification) differentially affected the utility of epidemiological data in identifying viable implementation neighborhoods across sites. In sites where PWID are more geographically dispersed, proximity to structural factors such as public transportation and spaces where PWID reside played a role in determining suitable implementation sites. The utility of leveraging additional data from local overdose and housing response systems to identify viable implementation neighborhoods was mixed. Conclusions Our findings suggest that data-driven approaches provide a contextually relevant pragmatic strategy to guide the real-time implementation of integrated care models to better meet the needs of PWID and help inform the scale-up of such complex interventions. This work highlights the utility of implementation science methods that attend to the impact of local community environmental factors on the implementation of complex interventions to PWID across diverse drug use, sociopolitical, and geographic landscapes in the US. Trial registration ClincalTrials.gov, Registration Number: NCT04804072. Registered 18 February 2021.

Background Safe injection self-efficacy (SISE) is negatively associated with injection risk behaviors among people who inject drugs (PWID) but has not been examined in differing risk environments. We compared responses to a validated SISE scale between PWID in San Diego, California and Tijuana, Mexico, and examine correlates of SISE among PWID in Tijuana. Methods PWID were recruited via street outreach for a longitudinal cohort study from October 2020 to September 2021. We compared SISE scale items by city. Due to low variability in SISE scores among San Diego residents, we restricted analysis of factors associated with SISE to Tijuana residents and identified correlates of SISE scores (low, medium, high) using ordinal logistic regression. Results Of 474 participants, most were male (74%), Latinx (78%) and Tijuana residents (73%). Mean age was 44. Mean SISE scores among San Diego residents were high (3.46 of 4 maximum) relative to Tijuana residents (mean: 1.93). Among Tijuana residents, White race and having previously resided in San Diego were associated with higher SISE scores. HCV and HIV seropositivity, homelessness, fentanyl use, polysubstance co-injection, and greater injection frequency were associated with lower SISE scores. Conclusions We found profound inequalities between Tijuana and San Diego SISE, likely attributable to differential risk environments. Associations with fentanyl and polysubstance co-injection, injection frequency, and both HIV and HCV seropositivity suggest that SISE contribute to blood-borne infection transmission risks in Tijuana. SISE reflects an actionable intervention target to reduce injection risk behaviors, but structural interventions are required to intervene upon the risk environment.

Background Opioid use and opioid overdose deaths are at an all-time high and evidence-based treatments for people with opioid use disorder (OUD) are underutilized. Therefore, we sought to understand experiences and perceptions of abuses in the for-profit substance use disorder treatment industry that could potentially put people with OUD at an increased risk for an overdose. Methods One-on-one semi-structured interviews were conducted from November 2018 to May 2019 in Southern California with 20 people with OUD and 20 professionals who work in the substance use disorder (SUD) treatment field. A grounded theory approach was conducted to discover emerging patterns from the data. Results Three major themes emerged:1) financial and material enticements, 2) encouraging substance use in the for-profit treatment sector, and 3) contributors to overdose risk. Participants reported that patient brokers would pay for plane tickets and offer financial incentives (e.g., money) to attract individuals to SUD treatment, capitalizing on insurance profits despite initial expenses. Participants reported being encouraged to use drugs before treatment to meet insurance conditions, thus jeopardizing genuine recovery efforts and adding to the temptation of drug use. Many participants linked patient brokering to increased overdose deaths, emphasizing the dangerous practices of brokers providing drugs, promoting relapse, and creating a revolving door of treatment, which compounds the overdose risk after periods of abstinence. Conclusions Patient brokering and unethical abuses in the for-profit treatment industry have caused some people with OUD to seek treatment for money and housing instead of seeking treatment to stop opioid use. The harmful treatment environment was seen as a barrier to care and an unwanted obstacle to overcome on the path to recovery.