A social network approach to improve HIV prevention and substance use treatment for people who use drugs

The National Institute on Drug Abuse awarded New York University $771,043 on March 15, 2026, under the Drug Use and Addiction Research Programs (CFDA 93.279) to conduct a hybrid type II implementation-effectiveness trial of a peer change agent intervention designed to increase pre-exposure prophylaxis and medication for opioid use disorder uptake among people who inject drugs.

The study, titled "A Social Network Approach to Improve HIV Prevention and Substance Use Treatment for People Who Use Drugs," will enroll 372 people who inject drugs in Los Angeles, California through peer chain referral sampling and randomize them into two arms: the LINKED (Leveraging Interpersonal Networks to Keep Engagement in PREP & MOUD) intervention, a social network-based peer intervention designed to motivate network members toward pre-exposure prophylaxis and medication for opioid use disorder uptake, or an equal-attention control arm focused on HIV and overdose risk assessment and prevention. Participants will complete booster sessions at 21 and 42 days post-intervention, with follow-up assessments at 6 and 12 months. Primary outcomes measure confirmed pre-exposure prophylaxis and medication for opioid use disorder uptake and persistence at both individual and network levels. All participants will receive opioid overdose prevention education and resources as standard services. The study integrates longitudinal mixed-methods research guided by the Exploration, Preparation, Implementation, and Sustainment framework and evaluated using the Reach, Effectiveness, Adoption, Implementation, and Maintenance framework.

The award runs through December 31, 2030, with place of performance in New York, New York. Work is conducted in partnership with a peer-led organization providing services to people who inject drugs in Los Angeles, an Ending the HIV Epidemic priority jurisdiction.

Abstract

This study will conduct a hybrid type II implementation-effectiveness trial of a peer change agent intervention designed to increase pre-exposure prophylaxis (PREP) and medication for opioid use disorder (MOUD) uptake among people who inject drugs (PWID). The study will be conducted in partnership with a peer-led organization providing services to PWID in LOS angeles, CA. LOS angeles is an ending the HIV epidemic (EHE) priority jurisdiction. This project builds upon the investigative team's extensive partnerships to address the persistently low uptake of PREP and MOUD among PWID by leveraging social network diffusion strategies. Guided by the exploration, preparation, implementation, and sustainment (EPIS) framework and evaluated using the reach, effectiveness, adoption, implementation, and maintenance (RE-aim) framework, the study will assess both effectiveness and implementation outcomes. A total of 372 PWID will be enrolled using peer chain referral sampling and randomized into one of two study arms: (1) linked (leveraging interpersonal networks to keep engagement in PREP & MOUD), a social network-based peer social network intervention designed to motivate network members to engage in PREP and MOUD uptake, or (2) an equal-attention control arm focused on HIV and overdose risk assessment and prevention. Participants will complete booster sessions at 21- and 42-days post-intervention, with follow-up assessments at 6 and 12 months. The primary outcome will be a confirmed PREP and/or MOUD uptake and persistence at the individual level and PREP and/or MOUD uptake at the network level. All participants, regardless of study arm, will receive opioid overdose prevention education and resources as part of standard services. The study will integrate longitudinal mixed-methods research to iteratively refine implementation strategies and evaluate key implementation outcomes at both the participant and HRO levels. Strong collaborations with PWID and the staff at our partner organization will ensure the feasibility and impact of the study. If effective, this trial will provide a scalable model to expand PREP and MOUD engagement among PWID in other EHE jurisdictions, strengthening HIV and overdose prevention efforts nationwide.