Abstract
<title>Abstract</title> <p>Background People who inject drugs (PWID) have played a central role in Vietnam’s HIV epidemic. Viral load (VL) testing remains uncommon among people living with HIV (PLHIV), particularly PWID. This study assessed the prevalence and determinants of detectable and high VL among HIV-positive PWID and described risk behaviors among those with detectable VL. Methods We analyzed data from HIV-positive PWID aged ≥ 18 years who reported recent injecting in the 2013 Integrated Biological and Behavioral Survey using time-location sampling (TLS) in three provinces (Dien Bien (DB), Yen Bai (YB), Nghe An (NA)) and respondent-driven sampling (RDS) in three cities (Hanoi (HN), Can Tho (CT), Ho Chi Minh City (HCMc)). Weighted prevalence estimates and logistic regression were used to assess VL levels and associated factors. Results High VL prevalence ranged from 8.4% (HN) to 23.6% (DB), while detectable VL ranged from 39.3% (HN) to 66.3% (YB). Among those on ART, high VL ranged from 0.0% (YB)–5.5% (DB) and detectable VL from 5.2% (CT) − 22.6% (YB). Province was significantly associated with detectable VL among ART users (OR = 0.2, CT vs. HCMc). Among participants with detectable VL, 78.5% (DB)–100.0% (YB) were not using opioid substitution therapy (OST); 5.2% (CT)–25.0% (HCMc) reported needle/syringe sharing; and 24.6% (HCMc)–55.5% (HN) reported unprotected sex. Conclusions A substantial proportion of PWID had detectable or high VL combined with ongoing risk behaviors and low OST use. Strengthening HIV testing, linkage to ART, and OST coverage for PWID is essential to reduce transmission and achieve national treatment targets.</p>