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SARS-CoV-2 viral RNA load dynamics in the nasopharynx of infected children.

  • Kam, K Q1, 2, 3
  • Thoon, K C1, 2, 3, 4
  • Maiwald, M2, 5, 6
  • Chong, C Y1, 2, 3, 4
  • Soong, H Y5
  • Loo, L H5
  • Tan, N W H1, 2, 3, 4
  • Li, J1, 2, 3
  • Nadua, K D1, 2, 3
  • Yung, C F1, 2, 4
  • 1 Infectious Disease Service, Department of Paediatrics, KK Women's and Children's Hospital, Singapore. , (Singapore)
  • 2 Duke-NUS Graduate Medical School, Singapore. , (Singapore)
  • 3 Yong Loo Lin School of Medicine, National University of Singapore, Singapore. , (Singapore)
  • 4 Lee Kong Chian School of Medicine, Imperial College London, Nanyang Technological University, Singapore. , (Singapore)
  • 5 Department of Pathology and Laboratory Medicine, KK Women's and Children's Hospital, Singapore. , (Singapore)
  • 6 Department of Microbiology and Immunology, National University of Singapore, Singapore. , (Singapore)
Published Article
Epidemiology and Infection
Cambridge University Press
Publication Date
Jan 11, 2021
DOI: 10.1017/S095026882100008X
PMID: 33427152


It is important to understand the temporal trend of the paediatric severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral load to estimate the transmission potential of children in schools and communities. We determined the differences in SARS-CoV-2 viral load dynamics between nasopharyngeal samples of infected asymptomatic and symptomatic children. Serial cycle threshold values of SARS-CoV-2 from the nasopharynx of a cohort of infected children were collected for analysis. Among 17 infected children, 10 (58.8%) were symptomatic. Symptomatic children, when compared to asymptomatic children, had higher viral loads (mean cycle threshold on day 7 of illness 28.6 vs. 36.7, P = 0.02). Peak SARS-CoV-2 viral loads occurred around day 2 of illness in infected children. Although we were unable to directly demonstrate infectivity, the detection of significant amount of virus in the upper airway of asymptomatic children suggest that they have the potential to shed and transmit SARS-CoV-2. Our study highlights the importance of contact tracing and screening for SARS-CoV-2 in children with epidemiological risk factors regardless of their symptom status, in order to improve containment of the virus in the community, including educational settings.

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