Norovirus shedding among symptomatic and asymptomatic employees in outbreak settings in Shanghai, China

BMC Infectious Diseases

Table 3 Factors correlated with the duration of norovirus shedding among infected employees using the Kaplan-Meier method

Variables	Participants n = 88 (%)	Mean (95% CI)	Shedding duration in different quartile (days)^a			P value
Variables	Participants n = 88 (%)	Mean (95% CI)	25%	50%	75%	P value
Gender						0.42
Male	47 (53.4)	7.2 (5.9–8.4)	9	7	3
Female	41 (46.6)	6.6 (5.7–7.4)	8	7	5
Age						0.12
0–39	63 (71.6)	6.6 (5.7–7.4)	8	7	4
≥40	25 (28.4)	7.7 (6.0–9.3)	9	8	5
Symptoms ^b
Yes	27 (30.7)	9.8 (8.2–11.4)	13	9	7	< 0.01
No	61 (69.3)	5.6 (5.0–6.3)	8	7	3
Total	88 (100.0)	6.9 (6.1–7.7)	8	7	4

^aShedding duration in different quartile, including 75, 50 and 25%, was used to indicate the corresponding proportion of NoV-infected employee still shedding virus at that time
^bIn the Cox proportional-hazards model after adjusting age and gender (male vs. female), shedding duration was still significantly longer in symptomatic norovirus-infected employees compared with asymptomatic ones (HR = 3.4, 95% CI: 1.9–5.9, P < 0.01)

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