Analysis of Factors Affecting the Nucleic Acid Negative Conversion Time after SARS-CoV-2 Omicron Variant Infection

Objective: To explore the influencing factors of nucleic acid negative conversion time of patients infected with the SARS-CoV-2 Omicron variant.Methods : Data from 455 Omicron inpatients at Huzhou Central Hospital from April 7 to May 31, 2022, were analyzed, and 408 were eligible for the study. The study compared the impact of clinical characteristics, vaccine status, underlying diseases, and treatment on nucleic acid negative conversion time. The Kaplan-Meier curve and Cox proportional hazard analysis were employed to evaluate the effect of different factors on the virus clearance time of Omicron infection.Results: 408 patients with a median age were 44 years old (IQR:32-52) and 80 (19.6%) with underlying diseases. Approximately 90% of cases received two or three doses of COVID-19 vaccinations. The multivariate Cox proportional hazard regression suggested that clinical classification (P < 0.001), history of underlying diseases (hazard ratio [HR], 1.426; 95% CI, 1.096-1.856; P = 0.008), anemia at admission (HR, 2.652; 95% CI, 1.091-6.442; P = 0.031), and use of glucocorticoids were independent risk factors (HR, 10.061; 95% CI, 1.298-77.997; P = 0.027) for slowing down the rate of virus-negative conversion and prolonging the duration of nucleic acid positive.Conclusion: The population was relatively young, less likely with chronic underlying diseases, and highly vaccinated in this study. There were no severe/critical cases. Moderate illness, history of underlying disease, anemia at admission, and use of glucocorticoids were independent risk factors for delaying virus-negative conversion time of Omicron infection. COVID-19 patient management and risk stratification may benefit from addressing the anemia problem and other underlying diseases in the future.