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

• Published in: Journal of medical virology Vol. 92; no. 10; pp. 2227 - 2231
• Main Authors: Carmo, Anália, Pereira‐Vaz, João, Mota, Vanda, Mendes, Alexandra, Morais, Célia, Silva, Andreia Coelho, Camilo, Elisabete, Pinto, Catarina Silva, Cunha, Elizabete, Pereira, Janet, Coucelo, Margarida, Martinho, Patrícia, Correia, Lurdes, Marques, Gilberto, Araújo, Lucília, Rodrigues, Fernando
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01-10-2020; John Wiley and Sons Inc
• Subjects: Adult; Aged; Aged, 80 and over; Child; clearance; Convalescence; Coronaviridae; Coronaviruses; COVID-19; COVID-19 - diagnosis; COVID-19 - immunology; COVID-19 - pathology; COVID-19 - virology; COVID-19 Testing - methods; Cross-Sectional Studies; Female; Humans; Illnesses; Immune clearance; Immune response; Immune system; Immunoglobulin G; Male; Middle Aged; Nasopharynx - virology; Oropharynx - virology; Patient Discharge - statistics & numerical data; Polymerase chain reaction; Respiratory diseases; Respiratory tract; Retrospective Studies; Reverse Transcriptase Polymerase Chain Reaction; Reverse transcription; Ribonucleic acid; RNA; RNA, Viral - genetics; RT‐PCR; SARS-CoV-2 - genetics; SARS-CoV-2 - immunology; SARS-CoV-2 - pathogenicity; SARS‐CoV‐2; Severe acute respiratory syndrome; Severe acute respiratory syndrome coronavirus 2; Severity of Illness Index; Short Communication; Short Communications; Signs and symptoms; Subgroups; Viral diseases; Virology; COVID-19; clearance; SARS-CoV-2; RT-PCR
• ISSN: 0146-6615; 1096-9071
• DOI: 10.1002/jmv.26103

Patients with coronavirus disease‐2019 may be discharged based on clinical resolution of symptoms, and evidence for viral RNA clearance from the upper respiratory tract. Understanding the severe acute respiratory syndrome coronavirus 2 (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 reverse transcription‐polymerase chain reaction (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 2 weeks and that persistence of viral RNA is not necessarily associated with severe disease but may result from a weaker immune response instead.
Highlights
Viral RNA was evaluated in two groups of patients: those who achieved two negative RT‐PCR tests and those who kept testing positive.
Patients were organized thereafter in two subgroups, mild and moderate/severe illness patients.
Most patients from either group tested positive for more than two weeks.
Mild illness patients maintained viral RNA for a longer period of time and presented lower IgG titers than moderate/severe illness patients.
We hypothesize that the exposition of mild illness patients to SARS‐CoV‐2 did not elicit an effective immune response, explaining the need of more time to viral RNA clearance.