Clearance and Persistence of SARS‐CoV‐2 RNA in COVID‐19 patients

Carmo, Anália; Pereira‐Vaz, João; Mota, Vanda; Mendes, Alexandra; Morais, Célia; da Silva, Andreia Coelho; Camilo, Elisabete; Pinto, Catarina Silva; Cunha, Elizabete; Pereira, Janet; Coucelo, Margarida; Martinho, Patrícia; Correia, Lurdes; Marques, Gilberto; Araújo, Lucília; Rodrigues, Fernando

COVID‐19 patients may be discharged based on clinical resolution of symptoms, and evidence for viral RNA clearance from the upper respiratory tract. Understanding the SARS‐CoV‐2 viral clearance profile is crucial to establish a re‐testing plan on discharge and ending isolation of patients. We aimed to evaluate the number of days that a patient needed to achieve undetectable levels of SARS‐CoV‐2 in upper respiratory tract specimens (nasopharyngeal swab and/or an oropharyngeal swab). The clearance and persistence of viral RNA was evaluated in two groups of positive patients: those who achieved two negative RT‐PCR tests and those who kept testing positive. Patients were organized thereafter in two subgroups, mild illness patients discharged home and inpatients who had moderate to severe illness. Results from RT‐PCR tests were then correlated with results from the evaluation of the immune response. The study evidenced that most patients tested positive for more than two weeks and that persistence of viral RNA is not necessarily associated with severe disease but may result from a weaker immune response instead. This article is protected by copyright. All rights reserved.