Modeling the early temporal dynamics of viral load in respiratory tract specimens of COVID-19 patients in Incheon, the Republic of Korea

• Published in: International journal of infectious diseases Vol. 108; pp. 428 - 434
• Main Authors: Lim, Ah-Young, Cheong, Hae-Kwan, Oh, Yoon Ju, Lee, Jae Kap, So, Jae Bum, Kim, Hyun Jin, Han, Boram, Park, Sung Won, Jang, Yongsun, Yoon, Chang Yong, Park, Yun Ok, Kim, Jong-Hun, Kim, Jin Yong
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.07.2021; The Authors. Published by Elsevier Ltd on behalf of International Society for Infectious Diseases; Elsevier
• Subjects: COVID-19; Natural history; RT-PCR; SARS-CoV-2; Viral load; Viral shedding; COVID-19; SARS-CoV-2; Viral shedding; Viral load; RT-PCR; Natural history
• ISSN: 1201-9712; 1878-3511
• DOI: 10.1016/j.ijid.2021.05.062

•The duration of isolation for COVID-19 patients remains uncertain.•Viral loads peaked within 4 days after symptom onset.•After reaching the peak, the viral loads rapidly decreased until days 10–15.•The time to negative conversion was longer in symptomatic patients.•Different quarantine policies should be applied depending on disease severity. To investigate the duration and peak of severe acute respiratory syndrome coronavirus 2 shedding as infectivity markers for determining the isolation period. A total of 2,558 upper respiratory tract (URT) and lower respiratory tract (LRT) specimens from 138 patients with laboratory-confirmed coronavirus disease were analyzed. Measurements of sequential viral loads were aggregated using the cubic spline smoothing function of a generalized additive model. The time to negative conversion was compared between symptom groups using survival analysis. In URT samples, viral RNA levels peaked on day 4 after symptom onset and rapidly decreased until day 10 for both E and RdRp genes, whereas those in LRT samples immediately peaked from symptom onset and decreased until days 15.6 and 15.0 for E and RdRp genes, respectively. Median (interquartile range) time to negative conversion was significantly longer in symptomatic (18.0 [13.0–25.0] days) patients than in asymptomatic (13.0 [9.5–17.5] days) patients. The more types of symptoms a patient had, the longer the time to negative conversion. The viral load rapidly changes depending on the time after symptom onset; the viral shedding period may be longer with more clinical symptoms. Different isolation policies should be applied depending on disease severity.