Temporal trends of population viral suppression in the context of Universal Test and Treat: results from the ANRS 12249 TasP trial in rural South Africa - Larmarange, Joseph; Diallo, Mamadou Hassimiou; McGrath, Nuala; Iwuji, Collins; Plazy, Mélanie; Thiébaut, Rodolphe; Tanser, Frank; Bärnighausen, Till; Orne-Gliemann, Joanna; Pillay, Deenan; Dabis, François; ANRS 12249 TasP Study Group
Background: The universal test-and-treat strategy (UTT) aims to maximize the proportion of all people living with HIV (PLWHIV) on antiretroviral treatment (ART) and virally suppressed in a community, i.e. to reach population viral suppression (PVS). The ANRS 12249 TasP trial did not demonstrate an impact of universal ART on HIV incidence at population level (Lancet HIV 2017). Here, we investigated whether PVS improved during the course of the trial: differentially by arm, according to trial interventions or contextual changes. Methods: The TasP cluster-randomized trial (2012-2016) implemented six-monthly repeated home-based HIV counselling and testing (RHBCT) and referral of PLWHIV to local HIV clinics in 2×11 clusters opened sequentially. ART was initiated according to national guidelines in control clusters vs. regardless of CD4 count in intervention clusters. Test results, clinic visits, ART prescriptions, viral loads, CD4 counts, migrations and deaths were used to produce information on residency status, HIV status and HIV care status for each participant. PVS was computed daily and per cluster among all resident PLWHIV (≥16, including those not in care). We used a mixed linear model to explore the relation between PVS with calendar time, time since cluster opening, trial arm and interaction between arm and time since cluster opening, adjusting on sociodemographic changes at cluster level. Results: 8,646 PLWHIV were observed. Between January 1st, 2013 and January 1st, 2016, PVS increased significantly in both arms (intervention: 29.0% to 46.2%, +17.2, p< 0.001; control: 32.4% to 44.6%, +12.2, p < 0.001), but difference in temporal variation (+5.0%) was not significant (p=0.175). According to adjusted model (figure) this increase was mainly attributable to RHBCT (measured by time since cluster opening). They were also some effect due to contextual changes (measured by calendar time). The effect attributable to universal ART (interaction term) was limited. Conclusions: Although suboptimal, the UTT strategy implemented in TasP trial improved PVS over time. As it was mainly due to RHBCT rather than universal ART, it did not induce differences between arms, explaining the null effect observed on cumulative incidence, the main trial finding. Changes in ART initiation guidelines alone are not enough to significantly increase PVS.
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