Table 1 Demographics and prevalence of norovirus infection for symptomatic and asymptomatic employees during outbreaks in Shanghai, from 2015 to 2017
Characteristics | Employees n = 421 | Asympa n = 377 | Asymp+ (%)b n = 64 (17.0) | Symptc n = 44 | Sympt+ (%)d n = 31 (70.5) | P Value |
|---|---|---|---|---|---|---|
Age (mean ± SD) | 38.8 ± 8.5 | 39.0 ± 7.9 | 39.0 ± 7.3 | 37.2 ± 12.3 | 37.4 ± 12.3 | 0.18 |
Gender | ||||||
Male | 277 | 249 | 35 (14.1) | 28 | 19 (67.9) | < 0.01 |
Female | 144 | 128 | 29 (22.7) | 16 | 12 (75.0) | < 0.01 |
Occupation | ||||||
Food handler | 236 | 226 | 45 (19.9) | 10 | 7 (70.0) | < 0.01 |
Cleaning staff | 73 | 69 | 9 (13.0) | 4 | 4 (100.0) | < 0.01 |
Teacher | 67 | 51 | 3 (5.9) | 16 | 8 (50.0) | < 0.01 |
Medical staff | 13 | 10 | 7 (70.0) | 3 | 2 (66.7) | 1.00 |
Others | 32 | 21 | 0 (0.0) | 11 | 10 (90.9) | < 0.01 |
Type of settings | ||||||
Kindergartens | 138 | 126 | 12 (9.5) | 12 | 10 (83.3) | < 0.01 |
Schools | 77 | 68 | 3 (4.4) | 9 | 2 (22.2) | 0.04 |
Hospitals | 7 | 4 | 1 (25.0) | 3 | 3 (100.0) | 0.14 |
Nursing home | 9 | 8 | 7 (87.5) | 1 | 0 (0.0) | 0.22 |
Hotel | 190 | 171 | 41 (24.0) | 19 | 16 (84.2) | < 0.01 |
Symptoms | ||||||
Average diarrhea episodes on the most severe day (mean ± SD) | 33 | 3.4 ± 2.3 | 3.3 ± 1.9 | |||
Average vomiting episodes on the most severe day (mean ± SD) | 21 | 2.6 ± 1.8 | 2.7 ± 1.9 | |||