Epidemiologic Features and Influencing Factors of Norovirus Outbreaks in the City of Wuxi, China from 2014 to 2018

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  • 1 Department of Disease Control, Wuxi Center for Disease Control and Prevention, Wuxi, Jiangsu, China;
  • | 2 Department of Public Health, Health Supervision Institute of Xinwu District, Wuxi, Jiangsu, China;
  • | 3 Department of Microorganism Labs, Wuxi Center for Disease Control and Prevention, Wuxi, Jiangsu, China;
  • | 4 Affiliated Hospital of Jiangnan University, Wuxi, Jiangsu, China;
  • | 5 Department of Pediatrics, Children’s Hospital of Shanghai, Shanghai, China

The study investigated the genotypic changes and epidemiologic features of norovirus outbreaks and factors influencing the attack rate and outbreak duration in Wuxi from 2014 to 2018. Norovirus outbreaks, monitored through surveillance system, were investigated. The norovirus-positive specimens from outbreaks were collected and genotyped using a dual polymerase-capsid genotyping protocol based on a one-step polymerase chain reaction (PCR) amplicon. The genotypes were analyzed by Norovirus Typing Tool Version 2.0. A total of 74 norovirus outbreaks were reported in Wuxi from 2014 to 2018. Most (93.2%) norovirus outbreaks were caused by GII genotypes. The predominant norovirus genotypes in outbreaks have changed from GII.17 (20.3%) in 2014–2015 to GII.P16/GII.2 (40.5%) in 2017–2018. GII.P16/GII.2 in 2017–2018 season were more prevalent than GII.17 in 2014–2015 season (χ2 = 4.741, P = 0.029). 56.7% of the outbreaks occurred in primary schools. The re-outbreak rate was 16.2%. 66.7% of re-outbreaks were caused by norovirus variants different from previous genotypes. Outbreaks in nonprimary school settings (odds ratio [OR]: 4.007; 95% CI: 1.247–12.876) and those leading to temporary school or institution closure (OR: 20.510; 95% CI: 1.806–232.937) were reported with a higher attack rate. The outbreaks in primary schools (OR: 4.248; 95% CI: 1.211–14.903), re-outbreaks (OR: 6.433; 95% CI: 1.103–37.534) and longer report timing (OR: 8.380; 95% CI: 2.259–31.089) declared a significantly longer duration. It is of great importance that the monitoring of norovirus outbreaks for the emergence of novel strains, along with responsive prevention and control intervention should be strengthened in adults and school-age population, especially in primary students and preschool children.

Author Notes

Address correspondence to Chao Shi, Department of Disease Control, Wuxi Center for Disease Control and Prevention, No. 499 Jincheng Rd., Liangxi District, Wuxi 214023, Jiangsu, China, E-mail: wxcdcshichao@126.com or Jie Gao, Department of Pediatrics, Children’s Hospital of Shanghai, No. 355 West Beijing Rd., Huangpu District, Shanghai 200040, China, E-mail: gaojie@shchildren.com.cn.

These authors equally contributed to the article.

Funding support: This research was supported by Wuxi Project of Double-Hundred Talent Plan (No. BJ2020100 and No. Z202019), Wuxi Key Medical Disciplines (ZDXK009), and Wuxi Suitable Technical Project of Health and Family Planning (T201819).

Authors’ addresses: Qian Geng, Department of Disease Control, Wuxi Center for Disease Control and Prevention, Wuxi, Jiangsu, China, and Department of Public Health, Health Supervision Institute of Xinwu District, Wuxi, Jiangsu, China, E-mail: cyrilwxgq@163.com. Yuan Shen, Ping Shi, Yu-Meng Gao, and Chao Shi, Department of Disease Control, Wuxi Center for Disease Control and Prevention, Wuxi, Jiangsu, China, E-mails: wxcdcshy@163.com, 149319082@qq.com, 947993788@qq.com, and wxcdcshichao@126.com. Wei-Hong Feng and Yong Xiao, Department of Microorganism Labs, Wuxi Center for Disease Control and Prevention, Wuxi, Jiangsu, China, E-mails: 827271291@qq.com and 229963517@qq.com. Xiaoying Ma and Shanshan Xie, Department of Public Health, Health Supervision Institute of Xinwu District, Wuxi, Jiangsu, China, E-mails: 67683509@qq.com and 316260634@qq.com. KeWei Wang, Affiliated Hospital of Jiangnan University, Wuxi, Jiangsu, China, E-mail: 578675475@qq.com. Jie Gao, Department of Pediatrics, Children’s Hospital of Shanghai, Shanghai, China, E-mail: gaojie@shchildren.com.cn.

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