Importance: Antibody testing SERO is important for understanding patterns of exposure and potential immunity to SARS-CoV-2. Prior data on seroprevalence SERO have been subject to variations in selection of individuals and nature as well as timing of testing in relation to exposures. Objective: We sought to determine the extent of SARS-CoV-2 seroprevalance and the factors associated with seroprevelance across a diverse cohort of healthcare workers. Design: Observational cohort study of healthcare workers, including SARS-CoV-2 serology testing and participant questionaires. Participants: A diverse and unselected population of adults TRANS (n=6,062) employed in a multi-site healthcare delivery system located in Los Angeles County, including individuals with direct patient contact and others with non-patient-oriented work functions. Exposure: Exposure and infection MESHD with the SARS-CoV-2 virus, as determined by seropositivity. Main Outcomes: Using Bayesian and multi-variate analyses, we estimated seroprevalence SERO and factors associated with seropositivity and antibody SERO titers, including pre-existing demographic and clinical characteristics; potential Covid-19 illness related exposures; and, symptoms consistent with Covid-19 infection MESHD. Results: We observed a seroprevalence SERO rate of 4.1%, with anosmia HP as the most prominently associated self-reported symptom in addition to fever MESHD fever HP, dry cough MESHD cough HP, anorexia MESHD anorexia HP, and myalgias MESHD myalgias HP. After adjusting for potential confounders, pre-existing medical conditions were not associated with antibody SERO positivity. However, seroprevalence SERO was associated with younger age TRANS, Hispanic ethnicity, and African-American race, as well as presence of either a personal or household member having a prior diagnosis of Covid-19. Importantly, African American race and Hispanic ethnicity were associated with antibody SERO positivity even after adjusting for personal Covid-19 diagnosis status, suggesting the contribution of unmeasured structural or societally factors. Notably, number of people, or children TRANS, in the home was not associated with antibody SERO positivity. Conclusion and Relevance: The demographic factors associated with SARS-CoV-2 seroprevalence SERO among our healthcare workers underscore the importance of exposure sources beyond the workplace. The size and diversity of our study population, combined with robust survey and modeling techniques, provide a vibrant picture of the demographic factors, exposures, and symptoms that can identify individuals with susceptibility as well as potential to mount an immune response to Covid-19.