2.1 Patients and controls
The current study was approved by the Institutional Ethics Committee of the Iraqi Ministry of Health. All participants were informed of the study objectives and agreed to participate in it through written consent. In this case-control study, 90 patients diagnosed with mild/moderate COVID-19 with a median age of 40 years and an interquartile range (IQR: 25-75%) of 33-46 years (60% males and 40% females) were enrolled. A control group (HC) of 90 blood donors matched patients for age (39 [IQR: 34-43] years) and gender (64.4% males and 35.6% females) was also enrolled in the study. The HC group included apparently healthy individuals, and serum tests for the blood bank antibody panel, including SARS-CoV-2 IgM and IgG antibodies, were negative. The study was conducted on patients admitted to healthcare units in Anbar Governorate due to signs and symptoms of COVID-19. Molecular examination of nasopharyngeal swabs confirmed infection with SARS-CoV-2 (RealLine SARS-CoV-2 kit, Bioron Diagnostics GmbH). In addition, sera of patients were tested for SARS-CoV-2 IgM and IgG antibodies (VIDAS SARS-CoV-2 IgM and IgG assay kits; bioMerieux, France). Inclusion criteria were positive molecular test, positive serum IgM antibody test, age ≥ 18 years, and mild/moderate disease as defined in WHO interim guidelines (WHO, 2020). Exclusion criteria were pregnancy and severe and/or critical COVID-19.