Residual viraemia does not influence 1 year virological rebound in HIV-infected patients with HIV RNA persistently below 50 copies/mL

Objectives: It is currently debated whether patients with residual viraemia are at higher risk of virological failure than those attaining <1 HIV RNA copy/mL. We therefore investigated the effect of residual viraemia on virological rebound. Methods: We used a prospective, non-interventional, single-centre, study. This analysis was based on HIV-infected patients with two consecutive HIV RNA viral loads (VLs) of <50 copies/mL as tested by Versant bDNA, followed by two HIV RNA VLs of <50 copies/mL as tested using the Versant kinetic PCR molecular system (kPCR; limit of quantification=1 copy/mL). Virological rebound was defined as two consecutive HIV RNA values of >50 copies/mL after baseline, and the time to virological rebound was calculated using the Kaplan-Meier method. Results: There were 739 eligible patients; 446 (60.4%) had HIV RNA <1 copy/mL (group A) and 293 (39.6%) had residual viraemia (1-49 HIV RNA copies/mL; group B). After a follow-up (median 48.9 weeks), virological rebound occurred in four patients in group A (0.9%) and six patients in group B (2%); the time to virological rebound was similar in the two groups (log-rank test P=0.231). CD4+ cell recovery (slope) was significantly less in the patients with residual viraemia; +14.3 (-7.7, 43.9) cells/mm(3) per year versus +21.2 (-22.5, 53.2) cells/mm(3) per year; P=0.036. Conclusions: Residual viraemia assessed by kPCR was not associated with virological rebound during 1 year of follow-up. However, the patients attaining <1 HIV RNA copy/mL showed a small but statistically significant improvement in CD4+ cell recovery.