The goal of this clinical trial is to evaluate the effectiveness of a social network intervention to recruit people who inject drugs and their networks for HIV testing and linkage to HIV prevention and treatment services in Maryland. Study aims are to determine the effectiveness of a social network driven intervention to increase:

• HIV testing (primary);
• PrEP knowledge;
• Uptake of HIV services and pre-exposure prophylaxis (PrEP);
• Uptake of medication for opioid use disorder (MOUD) initiation.

Eligible participants who access syringe service programs (SSPs) serving two counties in Maryland and their risk network members (NMs) will be recruited using an established network inventory and coupon recruitment method. When an index successfully recruits NMs, the index-NM cluster will be randomized to either a peer-educator intervention arm or an equal-attention control arm. Index participants randomized to the peer-educator intervention arm will complete a training program adapted with stakeholder input to context that emphasizes effective communication, frequent HIV testing, and awareness of evidence-based HIV prevention and treatment services. An important innovation to the network intervention will be training indexes to use and distribute HIV self-test kits and naloxone to their NMs. Index participants randomized to the equal-attention control arm will receive training sessions focused on the opioid overdose epidemic and will not include any training to serve as a peer educator. All participants (indexes and NMs) will complete study assessments at baseline and at 3 and 9 months. We will compare the peer-educator intervention group and the equal-attention control group on rates of HIV testing, knowledge of PrEP options and resources, and rates of initiation of HIV treatment, PrEP, and MOUD treatment since the previous assessment (past 3 or 6 months).

Inclusion Criteria:

Inclusion criteria for index participants:

• Aged 18 or older
• Self-reported injection drug use in the prior month
• Accessed services at the SSP in the prior 3 months
• Willing to undergo training and attend weekly booster group sessions
• Able to recruit at least 1 drug use Network Member (NM) into study
• Willing to talk with peers about PWID topics such as HIV prevention and care
• Not previously enrolled in the study as index or NM
• English-speaking

Inclusion criteria for network member participants:

• Aged 18 or older
• Self-reported injection drug use in the prior month
• Have a valid coupon or able to recall the 3-digit ID number
• Not previously enrolled in the study as index or NM
• English-speaking

Exclusion criteria:

• Individuals lacking the capacity to consent