Prevalence and correlates of low-level viremia and viral load non-suppression among adults on HIV treatment: Results from the Tanzania HIV Impact Survey, 2022-2023.

Abstract

While HIV viral load (VL) testing remained a critical approach for monitoring antiretroviral therapy (ART) effectiveness among people living with HIV (PLHIV), limited national data existed on the magnitude and factors associated with key VL thresholds, including low-level viremia (LLV) and VL non-suppression in Tanzania. We analyzed the prevalence and socio-demographic and behavioral factors associated with LLV and VL non-suppression among PLHIV on ART participating in a nationally representative survey. We analyzed data from the Tanzania HIV Impact Survey (THIS) 2022-2023 among PLHIV aged 15 years and older. The analysis included 1,485 PLHIV on ART with VL results. Laboratory-based testing was conducted for qualitative detection of antiretroviral (ARV) drugs and quantitative evaluation of VL. Three VL levels were computed for the analyses: undetectable VL (<50 copies/mL); LLV (50-999 copies/mL); and VL non-suppression (≥1000 copies/mL). Unweighted absolute numbers and weighted percentages were reported for descriptive analysis. We used modified Poisson regression models to examine separately the prevalence and factors associated with LLV and VL non-suppression. We reported adjusted prevalence ratios (aPR), 95% confidence intervals (CIs) and p-values <0.05 were considered statistically significant. Overall, 76% of PLHIV in Tanzania had undetectable VL, 18% had LLV, and 6% had VL non-suppression. Among PLHIV with either LLV or undetectable VL, 19.5% had LLV and after multivariable adjustment, absence of ARV drugs detected in blood was the only factor significantly associated with LLV. Additionally, among PLHIV with either VL non-suppression or undetectable VL, 7.2% had VL non-suppression and after multivariable adjustment, absence of ARV drugs detected in blood and alcohol use were associated with VL non-suppression. In this nationally representative analysis of PLHIV in Tanzania, most people had undetectable viral load, while LLV was common and VL non-suppression was less frequent. Absence of ARV drugs detected in blood was associated with both LLV and VL non-suppression, underscoring the importance of recent ART exposure. These findings suggested that LLV warranted programmatic attention alongside VL non-suppression to support sustained viral suppression.