Rationale and evidence for human immunodeficiency virus treatment as prevention at the individual and population levels.

Individual health benefits of antiretroviral therapy (ART) are becoming clearer. In resource-rich countries, side effects of current ART regimens are minimal. US guidelines recommend ART regardless of CD4 count or viral load. Maintaining an undetectable viral load with ART comes close to eliminating the risk of HIV transmission, leading the US guidelines to recommend universal ART to reduce HIV transmission. Achieving population-level control through treatment as prevention (TasP) may be feasible, but requires considerable investment of resources devoted to HIV testing, linkage to care, ART accessibility, and retention in care. Ongoing studies of TasP will provide insight into achieving meaningful ART coverage.