Viral shedding dynamics in asymptomatic and mildly symptomatic patients infected with SARS-CoV-2.

Abstract Objectives Asymptomatic patients, together with those with mild symptoms of COVID-19, may play an important role in SARS-CoV-2 transmission. However, the dynamics of viral shedding during the various phases of the clinical course of COVID-19 remains unclear at this stage. Methods A total of 18 patients found positive for SARS-CoV-2 infection by real-time reverse transcription PCR (RT-PCR) assay, and admitted to Chongqing University Central Hospital between Jan 29 and Feb 5 were enrolled in this study. Medical data, pulmonary CT scan images, and RT-PCR results were periodically collected during the patients’ hospital stay. All participants were actively followed-up for 2 weeks after discharge. Results A total of nine (50%) asymptomatic patients and nine 9 (50%) mildly mild symptom COVID-19 patients were identified on admission. Six (66.7%) asymptomatic patients on admission developed subjective symptoms during hospitalization were recategorized as ‘pre-symptomatic’. The median duration of viral shedding was 11.5, 28 and 31 days for pre-symptomatic, asymptomatic and mild symptomatic patients, separately. Seven (38.9%) patients continued to shed virus after hospital discharge. During the convalescent phase, detectable antibodies to SARS-CoV-2 and RNA were simultaneously observed in five (27.8%) patients. Conclusions Long-term viral shedding was presented in patients with mild symptoms and asymptomatic cases, and specific antibody production to SARS-CoV-2 may not guarantee viral clearance after discharge. These observations should be considered when making decisions regarding clinical and public health and strategies for prevention and control of SARS-CoV-2 infection.