About

Steffanie A. Strathdee is the Harold Simon Distinguished Professor in the Department of Medicine at the University of California San Diego School of Medicine. She is a co-director of UCSD’s center for Innovative Phage Applications and Therapeutics (IPATH) and the International Core of UCSD’s Center for AIDS Research. As an infectious disease epidemiologist, her research over the past two decades has focused on HIV prevention in marginalized populations in developing countries. She has published over 700 peer-reviewed publications and currently leads a multidisciplinary team studying HIV risk behaviors among people who use drugs on the Mexico-US border. Her work has earned her numerous awards and honors, including the Leadership Award in International Collaboration from the National Institute on Drug Abuse, a MERIT award from the same institute, and recognition as one of TIME's 50 Most Influential People in Health Care in 2018. She co-authored her memoir, The Perfect Predator, which details her efforts to seek bacteriophage therapy to save her husband from a multidrug resistant bacterial infection. Her research also includes revitalizing phage therapy in North America, and she is known for her contributions to science communication, harm reduction, and addressing antimicrobial resistance.

Selected publications

• From systems that harm to systems that heal: ending HIV requires confronting gender-based violence across the life course

  AIDS · 2026-04-29

  articleOpen accessSenior author
  PublisherOA PDFDOI

• PrEP as a “Hidden Message”: The Impact of Partner Dynamics on Oral PrEP Adherence Among Cisgender Women in Serodiscordant Relationships

  AIDS and Behavior · 2026-01-23

  articleOpen access

  BACKGROUND: Heterosexual sex accounts for 87% of new HIV diagnoses among cisgender women. We sought to explore the intersection of partner dynamics and oral preexposure prophylaxis (PrEP) adherence among cisgender women in heterosexual serodiscordant relationships. METHODS: From June 2017-August 2018, we conducted semi-structured in-depth interviews using a social ecological model framework. Twenty cisgender women in serodiscordant relationships, who participated in a PrEP demonstration project to evaluate adherence and retention in San Diego and Los Angeles, participated in in-depth interviews. Interviews were audio-recorded and transcribed, and transcripts were analyzed using thematic analysis. RESULTS: Among the 20 participants, the median age was 37.5 years (IQR 32, 48), with n = 6 (30%) identifying as Black and n = 5 (25%) as Hispanic. Sixty-five percent of women had protective drug levels based on real-time tenofovir-diphosphate drug level assays at the study visit prior to their interviews. Some partners played a significant role in PrEP adherence, often showing support by vocalizing encouragement and appreciation, offering reminders to take PrEP, and sometimes administering PrEP. Other partners were unsupportive and discouraged PrEP use, which may have hindered adherence. HIV and PrEP stigma were identified as potential barriers for women to take PrEP and disclose their PrEP use to others. CONCLUSIONS: Within the context of this PrEP demonstration project, partner dynamics impacted PrEP adherence for HIV-negative cisgender women in serodiscordant relationships. We urge further investigation of relationship dynamics and PrEP adherence and persistence specifically among US-based cisgender women.

  PublisherOA PDFDOI

• Impact of COVID-19 on late HIV diagnosis rates by race/ethnicity in Ending the HIV Epidemic (EHE) priority jurisdictions in the United States

  JAIDS Journal of Acquired Immune Deficiency Syndromes · 2026-04-15

  article

  INTRODUCTION: This study aims to determine the effect of the COVID-19 pandemic on changes in late HIV diagnoses by race/ethnicity across Ending the HIV Epidemic (EHE) priority jurisdictions in the US. METHODS: We analyzed annual county- and state-level (when county-level data were unavailable) late HIV diagnosis data in EHE priority jurisdictions from local epidemiological profiles and the AIDSVu between 2017-2022. Descriptive analyses were conducted to examine the percentages of late diagnoses across racial/ethnic groups before and after the onset of the pandemic. We then used interrupted time-series analysis to assess changes in both the level and trend of late diagnosis percentages across non-Hispanic White, non-Hispanic Black, and Hispanic populations. RESULTS: We included a total of 31 jurisdictions. The highest percentages of late HIV diagnoses were more often reported among Black or Hispanic populations. There were statistically significant (P<0.05) downward trends in late diagnosis percentages before the pandemic among the Black population in Kings County, NY(-3.8%), Georgia(-0.8%), and Los Angeles County, CA(-4.5%), and among the Hispanic population in Georgia(-4.9%). Subsequently, there were significant immediate increases in 2020 in the Black population in Kings County, NY(11.5%), Georgia(2.5%), and Los Angeles County, CA(10.8%), and among the Hispanic population in Georgia(11.5%). Additionally, there was a significant annual increase in the trend after the onset of the pandemic in both the Black(1.0%) and Hispanic populations(4.8%) in Georgia. In contrast, no statistically significant changes were found in the White population. CONCLUSIONS: The COVID-19 pandemic appears to have exacerbated existing race/ethnic disparities in late HIV diagnoses among several EHE jurisdictions.

  PublisherDOI

• “Bupe by the book”: A study protocol for a pilot randomized controlled trial of library-facilitated telehealth to increase buprenorphine treatment among individuals experiencing homelessness

  Addiction Science & Clinical Practice · 2025-09-17

  articleOpen access

  BACKGROUND: Accessing opioid use disorder (OUD) treatment is difficult for individuals with 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) that uses library resources to facilitate initiation and retention in OUD treatment with buprenorphine. METHODS: The study is 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 co-designed a pilot randomized controlled trial to assess the feasibility and acceptability of a library-facilitated telehealth intervention in San Diego, California. The intervention is being evaluated for its feasibility and acceptability (library tele-buprenorphine uptake) by obtaining an estimate of the effect of the library telehealth arm of the intervention on buprenorphine treatment outcomes (primary outcome: buprenorphine uptake, i.e., a pharmacy pickup and taking the prescription 1 + times) and adherence (i.e., > 1 buprenorphine positive screens, ideally for 8 + weeks), compared to the control (standard care at the clinic) intervention. Individuals reporting homelessness and OUD (with or without other substance use) are eligible. Forty library patrons will be recruited via flyers, screened for eligibility, and referred to FJV Health Center for in-person initial buprenorphine treatment intake visits. Participants who complete intake are enrolled and randomized to the library-facilitated telehealth condition, which involves using library internet and computer resources for follow-up buprenorphine treatment appointments with the medical provider via library telehealth. In the control condition, participants do not use library telehealth for their buprenorphine care follow up appointments, but rather they go in-person to the clinic or per usual standard care protocols. Feasibility and acceptability of the library telehealth intervention and conduct of the randomized controlled trial are determined by the participants' use of the library telehealth intervention for buprenorphine treatment, and quantitative and qualitative measures assessing their perceptions of the library telehealth intervention, collected over a 12-week period. DISCUSSION: The design of this pilot study may support the adoption of library-facilitated telehealth treatment as a feasible and acceptable strategy to engage and retain people experiencing homelessness with OUD in buprenorphine treatment. TRIAL REGISTRATION: This trial was registered prospectively at ClinicalTrials.gov (registration number NCT05872386) on May 24, 2023.

  PublisherOA PDFDOI

• US Overdose Mortality Saw First Drop Below the Jalal-Burke Exponential Growth Curve in 2024

  medRxiv · 2025-10-27 · 1 citations

  preprintOpen accessSenior author

  Background: Between 1979 and 2016, US overdose death rates rose in a smooth fashion, described by Jalal and Burke using an exponential growth curve that fit observed data nearly perfectly. Fluctuations above this curve have subsequently been seen during shocks related to drug supply and the COVID-19 pandemic. However, large-magnitude dips below the curve have never been demonstrated. Given that overdose mortality began sharply falling during 2023-2024, we assess updated overdose trends against the Jalal-Burke curve. Methods: We examined US overdose deaths from the National Vital Statistics System between January 1979-December 2024. We recreated the Jalal-Burke curve, fitting an exponential growth curve to overdose rates from 1979 to 2016, linearly projecting through 2024, with 95% confidence intervals. We also examined trends by specific substance involvement. Results: After precipitously surpassing exponential growth predictions in 2020-2023, overdose deaths decreased sharply from approximately 32 per 100,000 in 2021-2023 to 23.7 in 2024, falling below the lower bound of Jalal-Burke curve (24.98 per 100,000) for the first time since 2001. These decreases reflected declining illicit fentanyl-involved deaths (with and without stimulants); however, deaths involving stimulants without fentanyl, and those involving xylazine, represent an increasing share of deaths in 2024. Conclusions: Rather than simply representing a return to the Jalal-Burke exponential growth curve, recent decreases in overdose deaths represent the first significant, large-magnitude deviation below exponential growth projections. These trends represent a very positive development. However, challenges in the US drug crisis are shifting, requiring a tailored public health response.

  PublisherOA PDFDOI

• VANTAGE: van-based real-time HIV sequencing for transmission mapping and drug resistance profiling in war-affected Ukraine

  AIDS · 2025-12-04

  article

  We deployed the VANTAGE (VAN for Transmissible Agent Genomic Epidemiology) mobile system in Lviv, Ukraine, demonstrating end-to-end sequencing of dried blood spot samples within a clinic van usually serving de-occupied and frontline regions. HIV-1 pol sequences were obtained from 50% of samples, all subtype A6. Median time to 100× coverage was 38 min. Phylogenetic analysis revealed a local transmission cluster including a displaced person and the non-nucleoside reverse transcriptase inhibitor (NNRTI) resistance mutation E138A, supporting real-time HIV genomic surveillance in humanitarian crises.

  PublisherDOI

• A qualitative exploration of the downstream impact of a sustained disruption to the methadone supply in Mexico: effects on the mental, financial, and social health of patients with opioid use disorder in Tijuana

  The Lancet Regional Health - Americas · 2025-07-15

  articleOpen accessSenior author

  <h2>Summary</h2><h3>Background</h3> Medications for opioid use disorder (MOUD) are considered the gold standard long-term treatment for opioid use disorder (OUD) as they have a range of health and psycho-social benefits. Sudden reduction or interruptions in MOUD can have both immediate and long-term consequences for patients. We sought to qualitatively examine the impact of the prolonged closure of Mexico's main methadone production facility (<i>Psicofarma</i>) in 2023 on MOUD patients in Tijuana, Mexico. <h3>Methods</h3> We conducted semi-structured qualitative interviews with 20 MOUD patients in Tijuana, Mexico, from May to August 2023. We transcribed interviews and translated them from Spanish to English for analysis. Our analysis followed a thematic and narrative approach, and code congruency was found by consensus. Analytic and narrative memos provided the foundation for the ultimate findings. <h3>Findings</h3> The closure of <i>Psicofarma</i> resulted in a sudden stoppage in MOUD for participants. While some were provided with a benzodiazepine alternative and/or psychotherapy by their clinics, most were completely cut off from medical support. Participants reported returning to the illicit market for solutions to both withdrawal and drug cravings. Increased spending on the illicit market drained participant finances and strained employment and familial relationships. <h3>Interpretation</h3> The sudden interruption of MOUD treatment had varied yet predictable effects on our participants. These results demonstrate the need to ensure adequate methadone supply for people with OUD in Mexico and to offer other alternative therapies such as low-threshold buprenorphine. <h3>Funding</h3> Support for this study was provided by NIDA (R01DA049644-S4, T32DA023356 and DP2DA049295).

  PublisherOA PDFDOI

• Linkage to hepatitis C virus care in a binational cohort study of People who inject drugs on the U.S.-Mexico border

  International Journal of Drug Policy · 2025-06-19

  articleOpen access

  BACKGROUND: People who inject drugs (PWID) experience high rates of Hepatitis C Virus (HCV) infection in the U.S.-Mexico border region, but their care continuum is poorly characterized. METHODS: We analysed the HCV care continuum (linkage to care, initiation and completion of treatment) in a cohort of PWID in Tijuana, Mexico and San Diego. We also used multivariable Poisson regression to identify factors associated with linkage to HCV care among PWID in San Diego and Tijuana who reported prior HCV diagnosis. RESULTS: Among 133 PWID with active HCV infection in San Diego, 50.4 %, 16 % and 14.3 % reported prior awareness of their diagnosis; linkage to care and treatment completion; corresponding proportions for 21 PWID in Tijuana were 19 %, 14.3 % and 0 %. In multivariable analysis, factors independently associated with increased linkage to HCV care included receiving medication for opioid use disorder (MOUD) (Adjusted Prevalence Ratio [adjPR] 1.38; 95 % CI: 1.23-1.54) and HIV-seropositivity (adjPR 1.87 (95 %CI: 1.32-2.66). Tijuana residency (adjPR: 0.73; 95 % CI: 0.70-0.75) and younger age (adjPR 0.94 per 5-year age decrease; 95 % CI: 0.89-0.99) were independently associated with decreased linkage to care. Among PWID with a prior HCV diagnosis, 52.6 % and 40.7 % reported linkage to care in San Diego and Tijuana respectively. CONCLUSIONS: Our study shows poor linkage to HCV-related care among PWID in both San Diego and Tijuana, along with low treatment completion. MOUD programs could be an efficient touchpoint to improve access to HCV care.

  PublisherDOI

• Automated image analysis of instagram posts: Implications for risk perception and communication in public health using a case study of #HIV

  UNC Libraries · 2025-11-13

  articleOpen access

  People's perceptions about health risks, including their risk of acquiring HIV, are impacted in part by who they see portrayed as at risk in the media. Viewers in these cases are asking themselves "do those portrayed as at risk look like me?" An accurate perception of risk is critical for high-risk populations, who already suffer from a range of health disparities. Yet, to date no study has evaluated the demographic representation of health-related content from social media. The objective of this case study was to apply automated image recognition software to examine the demographic profile of faces in Instagram posts containing the hashtag #HIV (obtained from January 2017 through July 2018) and compare this to the demographic breakdown of those most at risk of a new HIV diagnosis (estimates of incidence of new HIV diagnoses from the 2017 US Centers for Disease Control HIV Surveillance Report). We discovered 26,766 Instagram posts containing #HIV authored in American English with 10,036 (37.5%) containing a detectable human face with a total of 18,227 faces (mean = 1.8, standard deviation [SD] = 1.7). Faces skewed older (47% vs. 11% were 35-39 years old), more female (41% vs. 19%), more white (43% vs. 26%), less black (31% vs 44%), and less Hispanic (13% vs 25%) on Instagram than for new HIV diagnoses. The results were similarly skewed among the subset of #HIV posts mentioning pre-exposure prophylaxis (PrEP). This disparity might lead Instagram users to potentially misjudge their own HIV risk and delay prophylactic behaviors. Social media managers and organic advocates should be encouraged to share images that better reflect at-risk populations so as not to further marginalize these populations and to reduce disparity in risk perception. Replication of our methods for additional diseases, such as cancer, is warranted to discover and address other misrepresentations.

  PublisherDOI

• Prevalence and Factors Associated With Sexually Transmitted Infections Among People who Inject Drugs in the San Diego–Tijuana Border Region

  Open Forum Infectious Diseases · 2025-03-21 · 1 citations

  articleOpen access

  Abstract Background Few estimates exist of the prevalence of sexually transmitted infections (STIs) and associated risk factors among people who inject drugs (PWID) in the San Diego–Tijuana border region, despite the high prevalence of HIV. Methods PWID living in San Diego or Tijuana underwent testing for bacterial STIs between December 2022 and February 2024. Urogenital gonorrhea and chlamydia infections were assessed using a urine test, the Aptima CT/GC assay. Syphilis was assessed using the treponemal Syphilis Health Check Rapid Point-of-Care assay and nontreponemal rapid plasma reagin Treponema pallidum Particle Agglutination test. HIV was tested using the fingerstick tests Miriad HCV/HIV POU+ Test and Oraquick HIV-1. Bacterial STI prevalence was calculated, and logistic regression was conducted to identify correlates of bacterial STI prevalence. Results Of 519 participants, 6.0% (95% CI, 3.9%–8.0%) tested positive for 1 or more bacterial STIs. Despite higher HIV prevalence in Tijuana, bacterial STIs were more prevalent in San Diego. Unstable housing, female birth, and US residency were associated with significantly higher adjusted odds of a bacterial STI compared with the reference groups (aOR, 2.61; 95% CI, 1.09–6.27; aOR, 2.41; 95% CI, 1.15–5.08; and OR, 2.79; 95% CI, 1.03–7.53; respectively). Conclusions Overall prevalence of bacterial STIs was consistent with other estimates of STIs among PWID in the United States. STI screening guidelines should recommend PWID for routine testing at least annually. Point-of-care testing should be expanded to increase access to STI screening and treatment for marginalized populations.

  PublisherOA PDFDOI

Education

• Doctor of Philosophy in Epidemiology , Department of Preventive Medicine and Biostatistics

  University of Toronto

  1994

• Master of Science in Epidemiology, Department of Preventive Medicine and Biostatistics

  University of Toronto

  1990

• Honors Bachelor of Science Degree Microbiology Specialist, Minor in English, Faculty of Arts and Sciences

  University of Toronto

  1988

Awards & honors

• Delta Omega Honorary Society in Public Health (1999)
• Member National Institute on Drug Abuse (2009)
• Award for Leadership in International Collaboration San Dieg…
• Women Who Mean Business Award POZ Magazine (2010)
• MERIT UC San Diego (2012)