Brief Report: HIV Incidence Among People Who Inject Drugs, San Francisco, 2022

Area of Science:

• Public Health
• Epidemiology
• Infectious Diseases

Background:

• Despite overall progress in reducing new HIV infections in San Francisco since 2012, a clear downward trend has not been observed among people who inject drugs (PWID).
• Direct measurement of HIV acquisition rates and identification of associated risk factors among PWID are crucial for achieving HIV elimination goals.

Purpose of the Study:

• To estimate HIV incidence among PWID in San Francisco.
• To identify factors associated with higher HIV seroconversion rates within this population.

Main Methods:

• Secondary analysis of the 2022 National HIV Behavioral Surveillance survey data from PWID in San Francisco.
• HIV incidence estimation using age at first injection drug use and date of first positive HIV test or interview.
• Cox regression analysis to identify factors associated with HIV seroconversion.

Main Results:

• The estimated HIV incidence among PWID was 0.46 per 100 person-years (95% CI 0.35-0.61).
• Significantly higher HIV incidence rates were found among men who have sex with men (aHR 15.98), transgender individuals (aHR 8.64), and Hispanic individuals (aHR 2.85).

Conclusions:

• A moderate HIV incidence of approximately 5 per 1,000 person-years was observed among PWID in San Francisco.
• Sexual, gender, and ethnic minority groups within the PWID population exhibited significantly higher HIV incidence rates.
• Enhanced scale-up of prevention interventions, such as pre-exposure prophylaxis (PrEP), is essential, particularly for vulnerable PWID groups, to achieve HIV elimination.