CD4 and COVID-19: In aggregated analysis, Eotaxin-3 and Eotaxin-1 levels decreased in COVID-19 patients; however, in sex-segregated analysis, Eotaxin-3, CCL5, IL-21, and IL6+CD4+ T cell levels were lower in female versus male HCW and this sex difference was maintained in female versus male COVID-19 patients (Figure 4b).