The purpose of our study was to determine whether the plasma biomarkers NfL, GFAP, UCHL1, or tau were higher in young adult participants with mild COVID-19 symptoms compared to young adult SARS-CoV-2-naïve participants, given that there is evidence of these biomarkers being elevated in older adults with moderate-to-severe COVID-19 symptoms. This evidence concerns the gene UCHL1 and COVID-19.