A prospective "test-and-treat" demonstration project among people who inject drugs in Vietnam.

Introduction: Modelling suggests that early diagnosis and immediate antiretroviral therapy (ART) among key populations would have a substantial impact in reducing HIV transmission and mortality in Vietnam. An implementation research project of "test-and-treat" among people who inject drugs (PWID) was developed to inform effective roll-out of such interventions.

Methods: "Test-and-treat" was offered to PWID in two high burden provinces, Thai Nguyen and Thanh Hoa. The interventions comprised the offer of biannual HIV testing and immediate ART, irrespective of CD4 count. PWID were enrolled between April 2014 and July 2015 and followed up for 12 months, and retention, HIV viral load (VL) and risk behaviours were assessed. Retention in care of this prospective cohort was compared with the retention among men enrolled in care in the preceding period (April 2012 to March 2013) at the same clinics when ART was initiated at CD4 cell count ≤350 cells/mm .

Results: In total, 287 HIV positive PWID started immediate ART. The majority (98%) were men; median age was 34; and median (interquartile range) CD4 count was 199 (50 to 402) cells/mm . After 12 months, 238 participants (83%) were retained on ART, and 205 achieved viral suppression (<1000 copies/mL) (92% among those in whom VL was measured, 71% overall). Baseline CD4 count ≤100 cells/mm and history of imprisonment were associated with lower retention and viral suppression, while engagement in methadone maintenance was associated with higher retention. Retention in care was higher in the "test-and-treat" cohort (83%) compared with men enrolled in care in the preceding period (78%), primarily because lost-to-follow-up during pre-ART care was eliminated. No decline in consistent condom use and clean needle use was observed.

Conclusions: Early ART initiation resulted in successful treatment outcomes among PWID, with no observed increase in self-reported risk behaviours, suggesting feasibility and potential effectiveness of "test-and-treat" approach. The results also call for differentiated care for PWID, including promoting early diagnosis and engagement in methadone maintenance therapy while enhancing care for those with advanced HIV disease and history of imprisonment.