BACKGROUND: The viral shedding duration of SARS-CoV-2 has not been fully defined. Consecutive detection of SARS-CoV-2 RNA from respiratory tract specimens is essential for determining duration of virus shedding and providing evidence to optimize the clinical management of COVID-19.

RESEARCH QUESTION: What are the shedding durations of SARS-CoV-2 RNA in upper and lower respiratory tract specimens respectively? What are their associated risk factors?

STUDY DESIGN: and Methods: A total of 68 patients with COVID-19 admitted to Wuhan Taikang Tongji Hospital and Huoshenshan Hospital from February 10, 2020 to March 20, 2020 were recruited. Consecutive SARS-CoV-2 RNA detection from paired specimens of nasopharyngeal swab (NPS) and sputum were carried out. The clinical characteristics of patients were recorded for further analysis.

RESULTS: SARS-CoV-2 RNA was detected from NPS in 48 (70.6%) patients, and from sputum specimens in 30 (44.1%) patients. The median duration of viral shedding from sputum specimens (34 days, IQR 24-40 days) was significantly longer than from NPS (19 days, IQR 14-25 days; P<0.001). Elderly age was an independent factor associated with prolonged virus shedding time of SARS-CoV-2 (HR 1.71, 1.01-2.93). It was noteworthy that in 9 patients the viral RNA was detected in sputum after NPS turned negative. Chronic lung disease and steroids were associated with virus detection in sputum, and diabetes mellitus was associated with virus detection in both NPS and sputum.

INTERPRETATION: These findings may impact a test based clearance discharge criteria given patients with COVID-19 may shed virus longer in their lower respiratory tracts, with potential implication for prolonged transmission risk. In addition, more attention should be given to elderly patients who might have prolonged viral shedding duration.


This content is not covered by the Open Government Licence. Please see source record or item for information on rights and permissions.

Cite as

Wang, K., Zhang, X., Sun, J., Ye, J., Wang, F., Hua, J., Zhang, H., Shi, T., Li, Q. & Wu, X. 2020, 'Differences of SARS-CoV-2 Shedding Duration in Sputum and Nasopharyngeal Swab Specimens among Adult Inpatients with COVID-19', Chest, 158(5), pp. 1804-1805. https://doi.org/10.1016/j.chest.2020.06.015

Downloadable citations

Download HTML citationHTML Download BIB citationBIB Download RIS citationRIS
Last updated: 17 June 2022
Was this page helpful?