Effect of SARS-CoV-2 Variants (Alpha, Beta, Delta, Omicron) on Inflammatory Parameters

Background: This study examined the changes in C-reactive protein (CRP), interleukin-6 (IL-6), white blood cell (WBC), neutrophil (NEU), lymphocyte (LYM), and eosinophil (EOS) parameters among severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) patient groups with Alpha (B.1.1.7), Beta (B.1.351), Delta (B.1.617.2), and Omicron (B.1.1.529) variants. Objectives: The present study aimed to examine the changes in CRP, IL-6, WBC, NEU, LYM, and EOS levels in patients infected with SARS-CoV-2 variants. Methods: Adults over the age of 18, who had a positive SARS-CoV-2 RT-PCR result and underwent molecular variant analysis (n = 40,133), were retrospectively included in the study. Changes in CRP (n = 7,712), IL-6 (n = 2,225), WBC (n = 6,885), NEU (n = 7,186), LYM (n = 8,224), and EOS (n = 7,901) parameters were analyzed in SARS-CoV-2 Alpha, Beta, Delta, and Omicron variant patient groups. Results: The incidence of women among patients with the Delta variant increased significantly (P = 0.001). The average age of Omicron variant patients was found to be higher (P < 0.001). In laboratory parameters, CRP levels were significantly higher in the Delta and Omicron variants compared to the others (P < 0.001). A decrease in the number of patients with high IL-6 values was observed from Alpha to Omicron (P < 0.001). The WBC values were significantly higher in the Delta variant than in the others (P < 0.001). Neutrophil levels were significantly higher in the Omicron variant (P < 0.001). There was an increase in the number of patients with normal LYM levels from Alpha to Omicron. Eosinophil levels were found to be lower in the Beta and Delta variants compared to the others (P < 0.001). Conclusions: The decrease in the number of patients with high IL-6 levels from Alpha to Omicron suggests that the rate of severe prognoses has decreased.