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

Abstract

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.

Keywords: COVID-19; Contact tracing; Coronavirus; Infectiousness; Isolation; RNA; Review; SARS-CoV-2; Virus culture.

Fig. 1

PRISMA diagram indicating the flow of inclusion of studies for review.

Fig. 2

Days since symptom onset at which SARS-CoV-2 virus culture was attempted (blue, patterned) and successful virus culturing (grey) took place in each study, displayed in descending order of last day of successful virus culturing.

Fig. 3

Probability curves presented in 3 studies (Singanayagam et al., van Kampen et al., Wölfel et al.) which attempted to model the probability of successful virus culture versus duration of days of symptoms., , Curves are presented with adaptation from the original presentation in the respective manuscripts in order to provide information for the first 20 days post symptom onset and to permit visual comparison of curves via overlay on a single plot. Lines (solid, dashed or dotted) depict estimated probability of positive virus culture versus days post symptom onset, while shaded areas depict 95% confidence intervals around these estimates.