Royal College of Surgeons in Ireland
The duration of infectiousness of individuals infected with SARS-CoV-2.pdf (954.73 kB)

The duration of infectiousness of individuals infected with SARS-CoV-2

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journal contribution
posted on 2020-12-17, 16:47 authored by Kieran A Walsh, Susan Spillane, Laura Comber, Karen Cardwell, Patricia Harrington, Jeff Connell, Conor Teljeur, Natasha Broderick, Cillian F de Gascun, Susan SmithSusan Smith, Mairin Ryan, Michelle O'Neill

Objectives: To summarise the evidence on the duration of infectiousness of individuals in whom SARS-CoV-2 ribonucleic acid is detected.

Methods: A rapid review was undertaken in PubMed, Europe PubMed Central and EMBASE from 1 January 2020 to 26 August 2020.

Results: We identified 15 relevant studies, including 13 virus culture and 2 contact tracing studies. For 5 virus culture studies, the last day on which SARS-CoV-2 was isolated occurred within 10 days of symptom onset. For another 5 studies, SARS-CoV-2 was isolated beyond day 10 for approximately 3% of included patients. The remaining 3 virus culture studies included patients with severe or critical disease; SARS-CoV-2 was isolated up to day 32 in one study. Two studies identified immunocompromised patients from whom SARS-CoV-2 was isolated for up to 20 days. Both contact tracing studies, when close contacts were first exposed greater than 5 days after symptom onset in the index case, found no evidence of laboratory-confirmed onward transmission of SARS-CoV-2.

Conclusion: COVID-19 patients with mild-to-moderate illness are highly unlikely to be infectious beyond 10 days of symptoms. However, evidence from a limited number of studies indicates that patients with severe-to-critical illness or who are immunocompromised, may shed infectious virus for longer.


Health Research Board (HRB-CICER-2016-1871)



The original article is available at

Published Citation

Walsh KA, Spillane S, Comber L, Cardwell K, Harrington P, Connell J, Teljeur C, Broderick N, de Gascun CF, Smith SM, Ryan M, O'Neill M. The duration of infectiousness of individuals infected with SARS-CoV-2. Journal of Infection. 2020;81(6):847-856.

Publication Date

9 October 2020

PubMed ID



  • General Practice
  • HRB Centre for Primary Care Research

Research Area

  • Population Health and Health Services




  • Accepted Version (Postprint)