Detection of HIV-1 at between 20 and 49 Copies per Milliliter by the Cobas TaqMan HIV-1 v2.0 Assay Is Associated with Higher Pretherapy Viral Load and Less Time on Antiretroviral Therapy

Abstract

New commercial techniques for determination of the viral load (VL) in plasma are able to detect as few as 20 copies of HIV-1 RNA/ml. The relevance of this new technical threshold is uncertain. Upon multivariate analysis, factors associated with detection of VLs between 20 and 49 copies/ml by the Cobas TaqMan HIV-1 v2.0 assay in an HIV clinic were the basal VL and time on antiretroviral therapy.

Comparative frequencies of HIV low-level viremia between real-time viral load assays at clinically relevant thresholds

“…Others have shown that patients who recently started ART (within 1-3 years) are more likely to experience LLV when transitioning to real-time PCR assays, which may explain our finding of an association with low CD4+ cell count. 18,19 These discrepant results could represent virus in early to middle phases of virological decay following treatment initiation. 9 Research studies with single copy sensitivity assays have demonstrated that HIV may be persistently detected when assays become more sensitive, as these assays reveal the inability to eradicate virus with current ART regimens even with intensification of treatment.…”

“…This LLV detected when switching test methods is reproducible and durable in selected patients, 17 is associated with the prior duration of undetectable VL 18 or the time since initiating ART, 18,19 and is not associated with subsequent treatment failure. 19,20 LLV has previously been described in patients serially monitored with a single test, sparking a scientific debate for the past decade on the optimal clinically relevant VL level that should be used as the goal for treatment. Prior publications using end-point PCR technologies to assess the clinical impact of VLs between 50 and 250 copies/mL found no significant correlation between intermittent LLV and subsequent virologic failure (VL > 1000 copies/mL), viral evolution, immunological failure, or progression of AIDSdefining illnesses.…”

Rapid identification of pathogens using molecular techniques

“…In addition, there is a trend emerging related to the concept of community viral load, which involves the use of viral load testing not simply for guiding patient treatment decisions, but also for public health analysis and planning. [120][121][122] Utility of determining bacterial load in septic shock using rapid tests Survival of septic shock is most influenced by early interventions [123][124][125] but the most widely adopted anti-inflammatory intervention has much less impact than antibiotics, 123,124 delayed, ineffective or insufficient doses of which all substantially increase mortality. 119 Recent HIV-1 studies have suggested that there is clinical value in detecting very low-level viraemia in HAART patients, with predictions of risk of virological rebound and failure while on therapy.…”

New Tools for Quantifying HIV-1 Reservoirs: Plasma RNA Single Copy Assays and Beyond

“…The set point to which residual viremia decays correlates with several parameters including 1) the level of pre-ART viremia [2••, 17], 2) the length of time between infection and treatment [5, 17, 18], 3) the duration of treatment [19, 20], and possibly 4) age [19], but not with CD4+ T-cell count or ART regimen [2••]. Immune activation does not appear to correlate with the residual viremia set point [20], but this issue has yet to be resolved fully.…”