The current DHHS guidelines define low-level viremia (LLV) as a confirmed detectable HIV RNA level of < 200 copies/mL. They consider virologic failure (VF) as “the inability to achieve or maintain suppression to an HIV RNA level of < 200 copies/mL.” Pending further studies and guidelines updates, how to best manage patients with LLV remains unclear.

This study from the U.S.-based HIV Research Network looked at the association between “viral blips” (HIV-RNA of 51-200 copies/mL) and LLV with VF. The study included 2,795 patients who were enrolled into care from 2005-2015 and who had a baseline HIV-1 RNA >200 c/mL. All were either ART-naïve (89%) or ART-experienced (11%) but not currently on treatment. Patients were included who achieved virologic suppression (≤ 50 on two consecutive VLs) but then had two subsequent detectable viral loads following suppression. Viral blips and LLV were categorized separately into three categories: no blips; LLV of 51-200; and VL of 201-500 copies. Cox proportional hazards regression was used to assess the association between rates of viral blips, LLV and VF (two consecutive VL >500).

During the 10 years of this study, 283 patients (10.1%) had virologic failure, 152 (5.4%) experienced LLV of 51-200 and 110 (4%) experienced LLV to 201-500. Both LLV of 51-200 copies as well as LLV of 201-500 copies were associated with virologic failure. However, in a sensitivity analysis of only the ART naïve patients, the association between LLV of 51-200 and virologic failure was not statistically significant.