Table 1.

Severity of illness and viral dynamics

	Classification of illness severity	Median (IQR*) duration of SARS-CoV-2 positivity in cohort, days	Viral dynamics in patients with severe illness vs those with non-severe illness	p value
Chen et al (2020)25	ICU vs non-ICU patients	11 (95% CI 10–12)	Median time to viral clearance significantly longer in ICU vs non-ICU patients (HR 3·17, 95% CI 2·29–4·37)	Only HR provided
Chen et al (2020)26	China CDC guideline (version 7)	12 (8–16)	Shedding duration varies by severity: asymptomatic 6 days; mild 10 days; moderate 12 days; serious 14 days; critical 32 days	<0·0001
Tan et al (2020)17	China CDC guideline (version 6)	Nasopharyngeal swab: 12 (range 3–38); any sample: 22 (range 3–38)	Viral shedding significantly longer in patients with severe illness: any sample 23 days vs 20 days (note that nasopharyngeal swab 14 vs 11 days was non-significant)	0·023 (any sample)
Xu et al (2020)36	WHO criteria	17 (13–32)	Higher proportion of patients with severe illness had shedding >15 days (34·2% vs 16·2%)	0·049
Yan et al (2020)37	China CDC guideline (version 6)	23 (18–32)	No difference in shedding duration (general illness 23 days vs severe illness 26 days vs critical illness 28 days)	0·51
Zheng et al (2020)23	China CDC guideline (version 6)	Respiratory sample: 18 (13–29)	Shedding duration significantly longer in patients with severe illness (21 vs 14 days) in respiratory samples; no difference in shedding duration in stool or serum samples	0·04

CDC=Center for Disease Control and Prevention. HR=hazard ratio. ICU=intensive care unit. SARS-CoV-2=severe acute respiratory syndrome coronavirus 2.

^*IQR unless otherwise stated.