Background: The present study aimed to compare serum total IgA levels between severe and mild COVID-19 patients' groups and the control group.
Methods: In this cross-sectional study, 216 definite severe COVID-19 patients (as the inpatient group), 183 subjects with positive specific COVID-19 IgG with mild or no symptoms as the (outpatient group), and 203 healthy subjects with negative specific serology, as the control group were investigated. The cases' laboratory data were collected, and thereafter, statistical tests, including independent samples t test, ANOVA test, and post hoc test, were performed using SPSS software version 22.