Dynamic changes of Ct values of N gene and ORF1ab genes and laboratory parameters in patients with COVID-19 caused by SARS-CoV-2 B.1, BA.2 and BA.5 variants and their correlation with clinical characteristics

Abstract

This study investigated the patterns of variation in the Ct values of the ORF1ab and N genes in oropharyngeal swabs of COVID-19 patients with different variants and to evaluate their associations with clinical and laboratory parameters. Total of 259 individuals with COVID-19 from 2021 to 2023 in Jilin Province were retrospectively included. Analysis was performed to compare the Ct values of the gene of SARS-CoV-2 in patients, with negative conversion time of nucleic acid, and the levels of blood tests during the patients' hospitalization.The majority of B.1 variant-infected individuals were asymptomatic; the median ORF1ab gene and N gene Ct values in oropharyngeal swabs from heavy patients were the lowest; and all ORF1ab gene Ct values were lower than N gene Ct values; with the longest negative conversion time of nucleic acid in these patients being 18 days.The median Ct values of the ORF1ab gene and the N gene were the highest in BA. 2 variant infected patients, and the Ct values of the ORF1ab gene and the N gene were higher in male patients than in female patients, and the shortest negative conversion time of nucleic acid was 14 days in patients with this variant, and the negative conversion time of nucleic acid was shorter in vaccinated patients than in unvaccinated patients.While the negative conversion time of nucleic acid was similar between BA.2 patients and BA.5 patients, the median Ct values of the ORF1ab and N genes were considerably lower in BA.5 patients than in BA.2 patients. The CREA, WBC, and NE% were significantly higher, and the ALB and LY% were significantly lower in BA.2 and BA.5 patients compared with B.1 patients. With disease aggravation, CREA, NE%, APTT, PT, and D-D increased, and LY% decreased. In conclusion, The most asymptomatic and longest transitional cycles were shown in patients with the ancestral lineage B.1 variation. Patients with the OmicronBA.2 variant showed the highest Ct values for the ORF1ab and N genes, while patients with the BA.2 and BA.5 variants had more serious coagulation and renal impairment.