The duration of transmissibility of coronavirus disease 2019 (Covid-19) and the associated level of contagion have been uncertain. We cultured severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in serial respiratory samples obtained from hospitalized patients with Covid-19 to assess the duration of shedding of viable virus.

The data reported here represent all the patients with Covid-19, as confirmed by positive real-time reverse transcriptase–polymerase chain reaction (RT-PCR) testing, who were hospitalized at Chung-Ang University Hospital in Seoul, South Korea, between February and June 2020. The Allplex 2019-nCoV Assay (Seegene) for nasopharyngeal and oropharyngeal samples was used for real-time RT-PCR testing. 1 Patients were isolated until two consecutive negative or inconclusive results on real-time RT-PCR were documented, at least 24 hours apart. 2,3 We endeavored to obtain samples at approximately 2-day intervals, but this was not always possible. Viral RNA was quantitated with the use of the cycle-threshold value for the N gene of SARS-CoV-2.4 Viral cultures were conducted by means of a plaque assay until at least two consecutive cultures showed no growth.

New England Journal of Medicine:

Min-Chul Kim, M.D., Ph.D.
Chung-Ang University Hospital, Seoul, South Korea

Chunguang Cui, M.Sc.
Kyeong-Ryeol Shin, M.Sc.
Joon-Yong Bae, Ph.D.
Korea University College of Medicine, Seoul, South Korea

Oh-Joo Kweon, M.D.
Mi-Kyung Lee, M.D., Ph.D.
Seong-Ho Choi, M.D., Ph.D.
Chung-Ang University Hospital, Seoul, South Korea

Sun-Young Jung, Ph.D.
College of Pharmacy, Chung-Ang University, Seoul, South Korea

Man-Seong Park, Ph.D.
Korea University College of Medicine, Seoul, South Korea
[email protected]

Jin-Won Chung, M.D., Ph.D.
Chung-Ang University Hospital, Seoul, South Korea
[email protected]