Regimen switching
VF, virological failure
Of the 78 study participants with virological failure (VF) at enrolment, 26 (33%) switched regimens after confirmation of VL ≥1,000 copies/ml. At enrolment, 37/237 (16%) of NNRTI-based first-line ART recipients had a VL ≥1,000 copies/ml and 21/237 (9%) of the participants who were on NNRTI-based ART were switched to PI-based second-line ART. In contrast, of the participants on a PI-based second-line regimen, 41/153 (27%) had confirmed VF, but only 5/153 (3%) switched to integrase strand transfer inhibitor (InSTI)-based third-line ART. The median (IQR) time to switch regimens from the first VL ≥1,000 copies/ml was 5.1 (3.9–10.0) months in SOC VL testing arm compared to 4.4 (2.5–8.4) months by the clinic-based SAMBA VL testing, (p = 0.569).