Health disparities in COVID-19: Immune and vascular changes are linked to disease severity and persist in a high-risk population in Riverside County, California (preprint)

ABSTRACT

Background Disparities in COVID-19 disease outcomes exist in Hispanic individuals, especially those with pre-existing health conditions. Infected individuals can develop “long COVID” with sustained impacts on overall quality of life. The goal of this study was to investigate the impact of COVID-19 infection and long COVID in Hispanic individuals and identify immune and endothelial factors that are associated with COVID-19 outcomes.Methods 112 participants in Riverside County, California, were recruited and categorized according to the following criteria healthy control (n = 23), moderate infection (outpatient, n = 33), and severe infection (hospitalized, n = 33). Differences in outcomes between Hispanic and non-Hispanic individuals and presence/absence of comorbidities were evaluated. Circulating immune and vascular biomarkers and immune cell subsets were measured by ELISA, multiplex analyte assays, and flow cytometry. Follow-up assessments for long COVID, lung health, and immune and vascular changes were conducted (n = 23) including paired analyses of the same participants.Results Compared to uninfected controls, the severe infection group had a higher proportion of Hispanic individuals (n = 23, p = 0.012), but there was no difference between uninfected controls and those with moderate infection (n = 8, p = 0.550). Disease severity was associated with changes in innate monocytes and neutrophils and lymphopenia, disrupted cytokine production (increased IL-8 and IP-10/CXCL10 but reduced IFNλ2/3 and IFNγ), and increased endothelial injury (myoglobin, VCAM-1). In the severe infection group, integration of parameters through machine learning identified NGAL/LCN2, IL-6, and monocyte activation as parameters associated with fatality, whereas anti-coagulant therapy was linked to survival. Recovery from moderate COVID infection resulted in long-term immune changes including increased monocytes/lymphocytes and decreased neutrophils and endothelial markers. This group had a lower proportion of comorbidities (n = 8, p = 1.0) but still reported symptoms associated with long COVID despite recovered lung health.Conclusion This study indicates increased severity of COVID-19 infections in Hispanic individuals of Riverside County, California. Infection resulted in immunological and vascular changes and long COVID symptoms that were sustained for up to 11 months, however, lung function (volume and airflow resistance) was recovered. Given the behavioral and immune impacts of long COVID, the potential for increased susceptibility to infections and decreased quality of life, especially in high-risk populations, warrants further investigation.