Virological assessment of hospitalized cases of coronavirus disease 2019

Abstract

This study presents a detailed virological analysis of nine hospitalized cases of COVID-19, revealing insights into the virus’s replication dynamics, infectivity, and antibody response. The study found that SARS-CoV-2 actively replicates in upper respiratory tract tissues, with high viral shedding in the throat during the first week of symptoms, even in cases with mild presentations. Infectious virus was readily isolated from throat and lung samples, but not from stool despite high viral RNA concentrations. The authors propose that efficient transmission occurs through pharyngeal shedding during the early, mild stages of infection, potentially explaining why COVID-19 is more easily transmissible than SARS. Additionally, the study highlights prolonged viral shedding in sputum, with implications for hospital infection control and discharge management. The authors propose using a combination of symptom duration and viral load in sputum to guide patient discharge decisions, ensuring that individuals are no longer infectious. Seroconversion occurred after 6-12 days, but was not followed by a rapid decline in viral loads, suggesting a potential for prolonged shedding despite the development of antibodies. – AI-generated abstract.