05 November 2025 : Clinical Research
Epidemiology of Norovirus Outbreaks in Kindergartens, Primary Schools, and Junior High Schools in Xi'an, China, From October 2020 to February 2023
Hui Zhang
ABCDEF 1, Xin-qian Gu BCDF 1, Lei-le Zhang BCDF 2, Chun-juan Wang BCDF 1, Zheng Wei ABCDEFG 3*
DOI: 10.12659/MSM.949902
Med Sci Monit 2025; 31:e949902
Table 3 Baseline characteristics of these 44 norovirus outbreaks reported to the Xi’an Center for Disease Control and Prevention from October 2020 and February 2023.
| Institution name | Timing of outbreaks | Total No. of cases | No. of cases tested | No. of cases with NoV detected | No. of exposed individuals | No. of exposed individuals tested | No. of exposed individuals with NoV detected | No. of cases with vomiting symptoms | No. of cases with diarrhea symptoms | Norovirus genome type |
|---|---|---|---|---|---|---|---|---|---|---|
| Kindergarten 1 | 2020/11/5 | 21 | 13 | 8 | 101 | / | / | 19 | 5 | GII |
| Kindergarten 2 | 2020/11/9 | 24 | 8 | 1 | 144 | 12 | 0 | 22 | 2 | GII |
| Primary school 1 | 2021/3/4 | 10 | 8 | 3 | 54 | / | / | 7 | / | GI |
| Kindergarten 3 | 2021/3/19 | 14 | 7 | 7 | 26 | / | / | 7 | / | GII |
| Kindergarten 4 | 2021/3/25 | 27 | 14 | 10 | 118 | 15 | 0 | 27 | 5 | GII |
| Secondary school 1 | 2021/4/2 | 19 | 15 | 8 | 67 | / | / | 9 | 12 | GII |
| Kindergarten 5 | 2021/4/2 | 10 | 7 | 7 | 25 | 9 | 3 | 10 | 4 | GII |
| Kindergarten 6 | 2021/4/16 | 14 | 6 | 5 | 23 | 8 | 1 | 14 | / | GII |
| Kindergarten 7 | 2021/4/16 | 7 | 7 | 1 | 35 | 4 | 0 | 4 | / | GII |
| Kindergarten 8 | 2021/4/23 | 13 | 9 | 3 | 37 | 11 | 1 | 9 | 1 | GII |
| Primary school 2 | 2021/4/23 | 8 | 7 | 4 | 53 | / | / | 7 | 1 | GII |
| Kindergarten 9 | 2021/4/28 | 12 | 13 | 9 | 34 | 1 | 0 | 12 | 3 | GII |
| Primary school 3 | 2021/4/29 | 10 | 10 | 1 | 55 | 7 | 0 | 10 | / | GI |
| Kindergarten 10 | 2021/5/10 | 14 | 5 | 2 | 56 | 5 | 0 | 14 | 5 | GII |
| Kindergarten 11 | 2021/5/12 | 16 | 9 | 8 | 54 | 9 | 0 | 16 | 2 | GII |
| Kindergarten 12 | 2021/5/20 | 14 | 13 | 10 | 84 | / | / | 14 | 4 | GII |
| Kindergarten 13 | 2021/5/27 | 31 | 18 | 14 | 219 | / | / | 31 | 4 | GII |
| Kindergarten 14 | 2021/6/30 | 17 | 14 | 10 | 33 | 2 | 0 | 17 | 3 | GII |
| Kindergarten 15 | 2021/9/6 | 16 | 10 | 10 | 34 | 10 | 6 | 15 | 3 | GI |
| Kindergarten 16 | 2021/9/10 | 17 | 9 | 8 | 23 | 2 | 0 | 17 | 3 | GII |
| Kindergarten 17 | 2021/12/8 | 8 | 3 | 3 | 26 | 6 | 1 | 8 | 2 | GII |
| Kindergarten 18 | 2021/12/13 | 19 | 7 | 4 | 30 | / | / | 19 | 11 | GII |
| Primary school 4 | 2021/12/21 | 55 | 18 | 14 | 2760 | / | / | 18 | 0 | GII |
| Primary school 5 | 2022/2/23 | 23 | 23 | 14 | 51 | / | / | 19 | / | GI |
| Kindergarten 19 | 2022/2/25 | 25 | 10 | 6 | 32 | 10 | 3 | 24 | 3 | GII |
| Kindergarten 20 | 2022/2/26 | 9 | 11 | 6 | 32 | 2 | 1 | 9 | 2 | GII |
| Primary school 6 | 2022/2/27 | 17 | 8 | 5 | 264 | 12 | 7 | 13 | 5 | GII |
| Kindergarten 21 | 2022/3/2 | 14 | 11 | 7 | 30 | 12 | 1 | 6 | 1 | GII |
| Kindergarten 22 | 2022/3/10 | 9 | 8 | 6 | 22 | / | / | 9 | 2 | GII |
| Kindergarten 23 | 2022/3/24 | 13 | 4 | 3 | 62 | 10 | 4 | 13 | 5 | GII |
| Kindergarten 24 | 2022/5/9 | 10 | 9 | 6 | 40 | 8 | 0 | 10 | 2 | GII |
| Kindergarten 25 | 2022/5/13 | 45 | 30 | 26 | 334 | 8 | 4 | 32 | 10 | GII |
| Primary school 7 | 2022/5/20 | 10 | 10 | 4 | 106 | / | / | 8 | 0 | GI |
| Kindergarten 26 | 2022/6/10 | 8 | 7 | 4 | 18 | / | / | 8 | 2 | GII |
| Kindergarten 27 | 2022/6/11 | 10 | 10 | 5 | 37 | / | / | 9 | 4 | GII |
| Kindergarten 28 | 2022/9/19 | 12 | 9 | 2 | 32 | 9 | 0 | 5 | 11 | GII |
| Kindergarten 29 | 2023/2/9 | 13 | 13 | 6 | 26 | 2 | 1 | 10 | 2 | GII |
| Kindergarten 30 | 2023/2/9 | 15 | 10 | 9 | 27 | / | / | 14 | 6 | GII |
| Kindergarten 31 | 2023/2/10 | 28 | 14 | 10 | 90 | / | / | 28 | 1 | GII |
| Primary school 8 | 2023/2/10 | 27 | 7 | 4 | 101 | 7 | 0 | 27 | 1 | GII |
| Kindergarten 32 | 2023/2/11 | 7 | 5 | 3 | 32 | 12 | 0 | 7 | 0 | GII |
| Secondary school 2 | 2023/2/14 | 52 | 6 | 2 | 2364 | / | / | 14 | 2 | GI |
| Kindergarten 33 | 2023/2/15 | 14 | 10 | 6 | 36 | 10 | 1 | 14 | 14 | GII |
| Primary school 9 | 2023/2/25 | 11 | 11 | 11 | 118 | 4 | 3 | 11 | 4 | GI |
| No. – number; / – no samples were collected from asymptomatic exposed individual. | ||||||||||