Crowell TA, et al. - In this work, clinical, virologic, and immunologic features of acute retroviral syndrome (ARS) were characterized and the impact of early antiretroviral therapy (ART) initiation was described. ARS, during acute HIV infection (AHI) and prior to ART, seemed correlated with a high viral burden, CD4 depletion and immune activation across multiple body compartments. In individuals who experienced ARS, persistent inflammation could contribute to increased morbidity despite suppressive ART.