Epidemiological and laboratory characteristics of Omicron infection in a general hospital in Guangzhou: a retrospective study

Abstract

The COVID-19 pandemic caused by SARS-CoV-2 has emerged as a major global public health concern. In November 2022, Guangzhou experienced a significant outbreak of Omicron. This study presents detailed epidemiological and laboratory data on Omicron infection in a general hospital in Guangzhou between December 1, 2022, and January 31, 2023. Out of the 55,296 individuals tested, 12,346 were found to be positive for Omicron. The highest prevalence of positive cases was observed in the 20 to 39 age group (24.6%), while the lowest was in children aged 0 to 9 years (1.42%). Females had a higher incidence of infection than males, accounting for 56.6% of cases. The peak time of Omicron infection varied across different populations. The viral load was higher in older adults and children infected with Omicron, indicating age-related differences. Spearman's rank correlation analysis revealed positive correlations between Ct values and laboratory parameters in hospitalized patients with Omicron infection. These parameters included CRP (r_s = 0.059, p = 0.009), PT (r_s = 0.057, p = 0.009), INR (r_s = 0.055, p = 0.013), AST (r_s = 0.067, p = 0.002), LDH (r_s = 0.078, p = 0.001), and BNP (r_s = 0.063, p = 0.014). However, EO (Eosinophil, r_s = -0.118, p < 0.001), BASO (basophil, r_s = -0.093, p < 0.001), and LY (lymphocyte, r_s = -0.069, p = 0.001) counts showed negative correlations with Ct values. Although statistically significant, the correlation coefficients between Ct values and these laboratory indices were very low. These findings provide valuable insights into the epidemiology of Omicron infection, including variations in Ct values across gender and age groups. However, caution should be exercised when utilizing Ct values in clinical settings for evaluating Omicron infection.

Keywords: Ct value; Omicron; age; laboratory biomarkers; sex.