Publications by authors named "Sa Strathdee"

In 2020, the in the county of San Diego (COSD) was launched, a private-public joint endeavor between the COSD and the American Liver Foundation. We use epidemic modeling to assess whether the COSD is on track to reach its elimination targets (80% reduction in incidence, 65% reduction in hepatitis C virus (HCV)-related mortality by 2030 compared to 2015) and what intervention scale-up may be required. We adapted a previously developed dynamic, deterministic model of HCV transmission and disease progression among adults in the COSD, stratified by risk, age, gender, and human immunodeficiency virus (HIV) status.

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Introduction: Drug use behaviors are closely associated with increased risk for HIV and other STIs among men who have sex with men (MSM) globally. Less is known about the drug use characteristics and their association with HIV/STI risk among MSM in Mexico, who have 13 times higher risk of acquiring HIV than the general population. We characterized distinct classes of drug use behaviors among a nationwide sample of MSM in Mexico and tested their associations with HIV risk behaviors.

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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.

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Background: Pre-exposure prophylaxis (PrEP) holds promise for decreasing new HIV infections among people who inject drugs (PWID), yet daily oral PrEP use is low, and PrEP modality and delivery strategy preferences in this population remain understudied.

Methods: From May 2022-June 2023, we conducted a discrete choice experiment (DCE) with PWID in San Diego, California. Participants viewed 18 PrEP program scenarios in sets of three and chose their preferred scenario within each set.

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Background: Travel restrictions implemented to mitigate the spread of SARS-CoV-2 decreased mobility and reduced physical contact during 2020-2021 for many in the general population. This analysis explored changes to network contacts among people who inject drugs (PWID) in the San Diego Border Region (SDBR) by cross-border mobility before and during the COVID-19 era.

Methods: Baseline data collected between October 2020-2021, from a cohort study of PWID in the SDBR were used to retrospectively describe differences in baseline characteristics across cross-border PWID groups (cross-border PWID [CB-PWID]: = 206; San Diego PWID [SD-PWID]: = 203; Tijuana PWID [TJ-PWID]: = 202).

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Background: In the United States, community overdose education and naloxone distribution (OEND) programs have demonstrated efficacy in reducing opioid-related mortality. OEND programs have expanded across San Diego County, California, but differential naloxone accessibility among people who use drugs (PWUD) has not been assessed. We examined factors that shape individual naloxone accessibility in San Diego.

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Background: The growing availability of big data spontaneously generated by social media platforms allows us to leverage natural language processing (NLP) methods as valuable tools to understand the opioid crisis.

Objective: We aimed to understand how NLP has been applied to Reddit (Reddit Inc) data to study opioid use.

Methods: We systematically searched for peer-reviewed studies and conference abstracts in PubMed, Scopus, PsycINFO, ACL Anthology, IEEE Xplore, and Association for Computing Machinery data repositories up to July 19, 2022.

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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.

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Antiviral therapies with reduced frequencies of administration and high barriers to resistance remain a major goal. For HIV, theories have proposed that viral-deletion variants, which conditionally replicate with a basic reproductive ratio [R] > 1 (termed "therapeutic interfering particles" or "TIPs"), could parasitize wild-type virus to constitute single-administration, escape-resistant antiviral therapies. We report the engineering of a TIP that, in rhesus macaques, reduces viremia of a highly pathogenic model of HIV by >3log following a single intravenous injection.

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Background: Illicitly manufactured fentanyl (IMF) increases overdose mortality, but its role in infectious disease transmission is unknown. We examined whether IMF use predicts hepatitis C virus (HCV) and human immunodeficiency virus (HIV) incidence among a cohort of people who inject drugs (PWID) in San Diego, California and Tijuana, Mexico.

Methods: PWID were recruited during 2020-2022, undergoing semi-annual interviewer-administered surveys and HIV and HCV serological rapid tests through 2024.

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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.

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Introduction: People who inject drugs (PWID) are at high risk of developing injection-related infections, including abscesses. Access to water, sanitation, and hygiene (WASH) are key human rights and services; yet these services have been underexplored as predictors of abscesses among PWID.

Methods: Longitudinal analysis was employed among a cohort of PWID to determine if WASH insecurity (lack of access) was associated with abscess incidence in the Tijuana, Mexico and San Diego, United States metropolitan area during 24-months of follow-up survey data from 2020 to 2023.

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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 - September 2021.

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Background: Domains of adequate menstrual health (MH) include access to water, sanitation, and hygiene (WASH). People who menstruate with social disadvantages-such as homelessness or drug injection practices-often face barriers to WASH access. However, validated instruments to measure MH are limited among marginalized populations, and available instruments involve lengthy surveys.

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Background: We examined HIV prevalence and transmission dynamics among people who inject drugs in the U.S./Mexico border region during the COVID-19 pandemic.

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Background: Amidst an increasingly toxic drug supply in North America, people who inject drugs may be transitioning to smoking them. We aimed to assess changes in injecting and smoking opioids and methamphetamine among a cohort of people who inject drugs from San Diego, California.

Methods: Over five six-month periods spanning October 2020-April 2023, we assessed prevalence of injecting and smoking opioids or methamphetamine and whether participants used these drugs more frequently by smoking than injecting.

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Background: Water, sanitation, and hygiene (WASH) access is critical to public health and human dignity. People who inject drugs (PWID) experience stigma and structural violence that may limit WASH access. Few studies have assessed WASH access, insecurity, and inequities among PWID.

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Background: Amidst a rapidly evolving drug supply in North America, people who inject drugs may be transitioning to smoking them. We aimed to assess changes in injecting and smoking heroin, fentanyl and methamphetamine among a cohort of people who injected drugs at baseline from San Diego, California.

Methods: Over five six-month periods spanning October 2020-April 2023, we assessed prevalence of injecting and smoking opioids or methamphetamine and whether participants used these drugs more frequently by smoking than injecting.

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Background: Incarceration is associated with drug-related harms among people who inject drugs (PWID). We trained >1800 police officers in Tijuana, Mexico on occupational safety and HIV/HCV, harm reduction, and decriminalization reforms (Proyecto Escudo). We evaluated its effect on incarceration, population impact and cost-effectiveness on HIV and fatal overdose among PWID.

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Article Synopsis
  • Long-acting injectable HIV pre-exposure prophylaxis (LAI-PrEP) could address challenges in HIV prevention for people who inject drugs (PWID) in the San Diego-Tijuana area, though awareness and interest in LAI-PrEP remain low among this group.
  • A study with 562 HIV-negative PWID revealed only 18% were aware of general PrEP, and factors like homelessness, fentanyl injection, and transactional sex were linked to this low awareness.
  • Interest was primarily in oral PrEP (44%), with LAI-PrEP interest at 25%, showing that those facing severe drug-related issues may prefer LAI-PrEP due to difficulties adhering to oral medication.
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Background: People who use drugs (PWUD) experience elevated HIV risk and numerous barriers to facility-based HIV testing. HIV self-testing (HIVST) could circumvent many of those barriers and is acceptable among PWUD, yet HIVST implementation for PWUD is limited. Service providers' perspectives on specific HIVST delivery strategies could help increase availability for PWUD.

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Background: HIV self-testing (HIVST) could increase HIV testing access among people who inject drugs (PWID), and secondary distribution (i.e., peer-delivery) of HIVST kits in PWID social networks could further expand coverage.

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Background: Water, sanitation, and hygiene (WaSH) insecurity increases the risk of water-related diseases. However, limited research has been conducted on psychosocial distress as it relates to WaSH insecurity, especially among people who inject drugs (PWID). We examined the relationship between WaSH insecurity and related anxiety among PWID living in different housing conditions along the US-Mexico border region.

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Background: Research is needed that investigates the relationship between police behaviors, attitudes, and perceived supervisor support as an implementation strategy of improving drug policy reforms.

Methods: We hypothesized that officers with more positive attitudes and practices would be more likely to report the perceived support of their supervisors. Data includes a sample of 1227 police officers who completed Project ESCUDO, a police education training program in Tijuana, Mexico.

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Background: We implemented a mentored research education and training program for underrepresented minorities (URMs) and Black, Indigenous, and People of Color (BIPOC) predoctoral and postdoctoral fellows called San Diego SUN (SD SUN): Supporting and Uplifting New and Diverse Scientists in HIV Research. The SD SUN program aimed to prepare fellows for an academic career trajectory in HIV science focused on ameliorating HIV-related disparities in communities of color.

Setting: The program leveraged a strong interinstitutional collaboration between San Diego State University and the University of California, San Diego, that share commitments to diversity, equity, and inclusion and an established history of training programs for URM/BIPOC investigators.

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