While social distancing is a key response to viral pandemics, social stress has been implicated in adverse health outcomes. A comprehensive understanding of the direct physiologic effects of social stress on viral pathophysiology is needed. To determine the effect of social stress on HIV pathogenesis during acute viral infection without sociobehavioral confounders inherent in human cohorts, we compared commonly measured parameters of HIV progression between singly and socially housed SIV-infected pigtailed macaques (Macaca nemestrina). Singly housed macaques demonstrated lower CD4/CD8 ratios, greater CD4 T cell declines and greater T cell activation compared to socially housed macaques during acute SIV infection. Singly housed macaques furthermore had higher viral loads in the plasma and cerebrospinal fluid throughout acute infection. These data demonstrate that social stress directly impacts the pathogenesis of acute lentiviral infection and imply that social stress has a direct effect on the pathogenesis of HIV and potentially other viral infections.### Competing Interest StatementThe authors have declared no competing interest.

Social Stress Alters Immune Response and Results in Higher Viral Load During Acute SIV Infection in a Pigtailed Macaque Model of HIV