The COVID-19 Pandemic, which became widespread in the United States in March 2020, has directly impacted nearly everyone in our country. An exceptionally large number of Americans have contracted the SARS-CoV-2 virus. The long-term effects of being infected by the virus are unknown, but it is evident that many of those who contracted the virus are continuing to exhibit severe cognitive and psychological impacts months after becoming infected. While the pandemic has affected everyone in some way, it may have disproportionately impacted those who are the most vulnerable of our population, including those who are homeless. Homelessness in Veterans is a major national issue, and the pandemic has only heightened the need to address the issue. Many homeless Veterans either lived in unsheltered environments or in congregate settings that may have limited their ability to socially distance, putting them at increased risk for infection. Furthermore, those who have recently obtained housing often face a disruption in their daily routines and social and family networks, which may have been exacerbated by the pandemic. This, in turn, could have further reduced social integration and resulted in increased mental health burden. Critical knowledge gaps exist in that we do not know how long negative cognitive and mental health outcomes from infection last, how pervasive they are in those who have been infected, or how infection affects vulnerable Veterans (for this proposal, Veterans with a history of chronic homelessness). This research proposal will address these crucial knowledge gaps by examining the effects of infection on cognitive functioning, mental health, and social integration in recently housed Veterans vs. Veterans without a history of chronic homelessness. In an exploratory aim, we will examine if risk and protective factors (resilience, coping, tolerance of uncertainty) and VA service utilization buffered the negative effects of infection. In the proposed 4-year study we will recruit a total of 400 Veterans across four large metropolitan areas (Los Angeles, Houston, Orlando, and Seattle) using VA databases to identify those who have been infected and have a history of chronic homelessness. There will be four groups in total, with 100 participants in each group, consisting of those infected vs. never infected and those with or without a history of chronic homelessness. All participants will be assessed remotely every 2 months over an 18-month period. By identifying the impact of COVID infection on vulnerable and non-vulnerable Veterans, this study can provide valuable information not available in any VA database or other study. The VA must plan for and provide effective treatment strategies to combat long-term effects of infection as the pandemic moves into the endemic phase. The results from this study will help guide interventions and treatments that ultimately are aimed at improving community integration in vulnerable Veterans and Veterans who m...