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Shifting Patterns of Injection Drug Use in San Francisco, United States: implications for Getting to Zero HIV
Gabriel Tariq Xavier Salomão de Pina1, Bow Suprasert2, Rachel Brandão Raskin1
1Faculdade de Ciências Médicas da Santa Casa de São Paulo, R. Jaguaribe, São Paulo, Brazil.
Substance Use & Misuse
|February 11, 2026
Summary
Methamphetamine is now the most injected drug among people who inject drugs in San Francisco, replacing heroin. This shift, alongside rising fentanyl use, is linked to increased HIV risk and necessitates urgent scaling of prevention methods like PrEP.
Area of Science:
- Public Health
- Epidemiology
- Substance Use Research
Background:
- Analyzing drug injection trends and associated HIV risks among people who inject drugs (PWID) is crucial for targeted public health interventions.
- Understanding shifts in primary drug use among PWID in San Francisco provides insights into evolving HIV transmission dynamics.
Purpose of the Study:
- To examine trends in the most frequently injected drugs among PWID in San Francisco from 2018 to 2024.
- To investigate the associations between specific injected drugs and HIV risk behaviors within this population.
Main Methods:
- Utilized data from National HIV Behavioral Surveillance serial cross-sectional surveys conducted in 2018, 2022, and 2024.
- Employed respondent-driven sampling for participant recruitment and multinomial logistic regression for trend analysis, adjusting for demographic factors.
- Conducted secondary analyses to explore trends by age and race/ethnicity and associations with risk behaviors.
Main Results:
- Methamphetamine injection prevalence increased significantly (23.9% to 55.7%), while heroin decreased (52.5% to 15.8%), and fentanyl rose (0.9% to 11.3%).
- These drug use shifts were observed earlier in younger and Hispanic PWID, and later in Black/African American PWID.
- Methamphetamine users showed the highest HIV prevalence (12.7%), while fentanyl users had the highest rates of condomless sex (64.4%) and injection equipment sharing (54.0%).
Conclusions:
- Methamphetamine has replaced heroin as the primary injected drug in San Francisco, with a notable increase in fentanyl use.
- The observed drug trends are associated with elevated HIV risks, highlighting the urgent need to scale up effective prevention strategies, including pre-exposure prophylaxis (PrEP).
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