In addition to standard HCV results disclosure for the comparator arm, intervention participants will have two counseling sessions:

Session 1: Immediately after HCV results disclosure, a staff-facilitated session with the index to (1) Establish HCV Treatment Goals, fostering commitment, and (2) Engage the Injecting Partner, identifying ways to support treatment initiation.

Session 2: One week later, involving both the index and injecting partner, to (1) Enhance Partner Support with specific strategies for HCV treatment initiation and (2) Collaborative Navigation Mapping, using a "navigation map" tool. By Session 2's end, both will have a completed navigation map, a visual guide for the HCV treatment journey.

Both sessions stress communication and dyadic coordination. The "navigation map" tool ensures a personalized plan for the index's treatment initiation and the partner's supportive navigator role.

Standard of care HCV disclosure. This staff-facilitated session follows the California HIV/HCV test counselor certification protocol with the Index alone.

A two-session, disclosure counselor-led, behavioral intervention to enable the injecting partner to support and navigate the adult PWID to start HCV treatment.

Assessed by comparing the proportion of those enrolled in the intervention group who initiated treatment to the proportion of those enrolled in the control group who initiated treatment at 6 months, 12 months, and 24 months after HCV infection disclosure visit.

Self-reported level of partner support measured at baseline, 1 week, 1 month, 3 months, and 6 months. Partner support is measured with a validated survey scale (range 1-5) where the higher the value the higher the partner support.