Factors Influencing Viral Clearance in Mild COVID-19 and Clinical Characteristics of Asymptomatic Patients

Background. The outbreak of coronavirus disease (COVID-19) has become a global public health emergency. Objective. To evaluate the characteristics and outcomes of patients with COVID-19 in Anhui and to identify predictors of viral clearance. Methods. We retrospectively analyzed the data collected from discharged patients with laboratory-confirmed SARS-CoV-2 infections. We compared clinical features between viral clearance and viral persistence, and evaluated factors associated with SARS-CoV-2 shedding using multiple linear regression. Results. Among the 83 patients involved in the study, the median age was 43 years, while 60.2% were male, 35.4% had comorbidities, and the mortality was zero. The median time from illness onset to admission was 5 days (interquartile range (IQR), 2-7 days), and the median time from the illness onset to SARS-CoV-2 RNA detection was 16 days (IQR, 13-18 days). The factors influencing viral clearance were as follows: (1) delayed admission (beta 1.057, 95% CI 0.810-1.304; p≤0.001) and (2) underlying comorbidities (beta 1.907, 95% CI 0.198-3.616; p=0.029). No significant differences were observed in the length of stay (p=0.246) and pneumonia between asymptomatic and symptomatic patients based on computed tomography (CT) (p=0.124). Conclusions. Delayed admission and underlying comorbidities may effectively predict SARS-CoV-2 RNA clearance. For those infected with SARS-CoV-2, even asymptomatic patients without any clinical symptoms should be traced and isolated. This practice may reduce the spread of SARS-CoV-2 and slow the COVID-19 pandemic caused by the virus. Clinical Trial Registration Number: This trial is registered with 2020-051