Evaluation of the transmissibility of norovirus and the effectiveness of prevention and control measures for schools in Jiangsu Province

Abstract

Objective

This study aims to estimate the transmissibility of norovirus outbreaks in schools by different transmission routes, and to evaluate the effects of isolation, school-closure and disinfection measures under different intervention intensities, finally, scientific prevention and control suggestions are proposed.

Method

23 outbreaks of norovirus infectious diarrhea occurring in Jiangsu Province’s school from 2012-2018 were selected and fitted to the model. The data includes various types of school places and pathogen genotype. A ‘SEIAQRW’ model with two transmission routes was established. The transmissibility of each outbreak was assessed using effective reproduction number, the efficacy of different intervention measures and intensities were evaluated by calculating the total attack rate and peak incidence.

Results

The mean effective reproduction number of noroviruses was estimated to be 8.92 for the human-to-human route of transmission and 2.19 for the water or food-to-human route of transmission. When all symptomatic cases were isolated, the median peak incidence for both transmission routes both being less than 1.8%. There was a smaller reduction in total attack rate compared to peak incidence, the median total attack rate for the two transmission routes decreased by 17.59% and 42.09%, respectively. When the effect of school-closure or disinfection is more than 90%, the total attack rate and peak incidence in the human-to-human route are reduced by more than 90% compared to no intervention, and the peak incidence in the water or food-to-human routes can be reduced to less than 1.4%, but the reduction in the total attack rate is only 50% or so.

Conclusion

Norovirus outbreaks have a high rate of transmission in schools. In the case of norovirus outbreaks, isolation should be complemented by other interventions, and the implementation of high-intensity school closures or disinfection of the external environment can be effective in reducing the spread of the virus.

Keywords:

• Norovirus
• transmissibility
• total attack rate
• peak incidence

Acknowledgements

Not applicable.

Authors contributions

JW and TC designed this study. JR, YZ and JH collected all required data. JW, JR, and TC contributed to the conception of the study. JW and XG designed the model and analyzed data. JW, YZ and BA calculated the transmissibility of this outbreak, JW, JR, BZ and YS draw all figures and tables. JW and JR were major contributors to write the manuscript. JW and JR contributed significantly to analysis and manuscript preparation. TC and JH helped perform the analysis with constructive discussions. All authors read and approved the final manuscript.

Ethics approval

This study did not involve animal experiments, human experiments and other contents that require ethical review, and only performed statistical analysis of public report card data. All data were given by Zhu Yuanzhao’s research, and the use of data has obtained permission from Zhu Yuanzhao as a participant in this study ([email protected]). We confirm that all experimental protocols were approved by ethics committee of School of Public Health in Xiamen University.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

All data and associated code can be found on GitHub (https://github.com/WangJing2478/NorovirusJiangsu).

Additional information

Funding

This study was supported by grants from the research project on education and teaching reform of undergraduate universities of Fujian Province, China (FBJG20210260) and Jiangsu Provincial Medical Key Discipline (No. ZDXK202250). The funder had no role in study design, data collection, data analysis, data interpretation, or writing of the report.