Table 1 Multiple viral load (VL) indicators and their definitions

Viral suppression: a confirmed HIV RNA level below 200 copies/ml

 •Initial VL at HIV diagnosis

 •The current/most recent VL

Viral rebound: confirmed HIV RNA level ≥ 200 copies/ml after viral suppression

 •Most recent viral rebound

Viral failure: the inability to achieve or maintain suppression of viral replication to an HIV RNA level < 200 copies/ml

Viral blip: After viral suppression, an isolated detectable HIV RNA level (≥200 copies/ml) that is followed by a return to viral suppression

Low-level viremia: Confirmed detectable HIV RNA level <1000 copies/ml (at least two consecutive VL measures above 1000 copies/ml)

Aggregate feature:

 •Nadir VL

 •Peak VL

 •Number of viral rebounds

 •Size of the viral rebound (none, 500–1000, 1000–10,000 and > 10,000 copies/ml)

Longitudinal feature:

 •Time to initial viral suppression

 •Time since the most recent viral rebound

 •Sustained viral suppression: patients with VL< 200 copies/ml in every VL measurement throughout the study period

 •Proportion of time spent with viral suppression (< 200 copies/ml)

 •Level of viral rebound (low level: at least 2 VL values were 500–5000 copies/ml; high-level: at least 2 VL values were >500 copies/ml)

 •Intermittent LLV: VL of 200–1000 copies/ml on < 25% of measurements

 •Persistent LLV: VL of 200–1000 copies/ml on ≥ 25% of measurements