The outbreak of acute gastroenteritis caused by sapovirus at a school in Shenzhen, China, 2023

Background: Between February 6 and 8, 2023, an increasing number of students showed symptoms of vomiting in a school in Shenzhen, China. To identify the cause of this outbreak and curb disease spread on February 9, 2023, and an outbreak investigation including a case-control study was conducted. Methods: A structured questionnaire was used to collect the symptoms of all cases, a retrospective cohort study were conducted to examine the risk factors for diarrhea or vomiting. To find the contamination source, we investigated the environment all buildings in schools. Relative risk was presented and Chi-square test was performed. All the analyses were performed with OpenEpi software version 2.3.1 online. PCR was used to test stool specimens. Results: This outbreak was caused by sapovirus, and lasted for 9 days. 70.9% of cases reported vomiting, 53.5% diarrhea, 38.4% bellyache, 14.0% feel nauseous, and 69.6% had diarrhea no more than twice. Eating food provided by the school or drinking water from direct-drinking machine was not associated with the acquisition of AGE based on univariate analysis. The students who had passed near a spot of vomit (<2.4 m) were more likely to get AGE with a relative risk of 5.09 (95%CI: 2.58, 10.04). The case number with AGE in classrooms using standard operating procedure for vomit cleanup is obviously lower than that in ones not handling vomit according to the standard procedure [relative risk (RR):0.34, 95%CI: 0.15, 0.77]. Conclusion: Sapovirus was the causative agent of this AGE outbreak, and airborne transmission was the primary route of infection. Prompt decontamination and the use of vomit bags significantly reduce the incidence of AGE while close contact with contaminated materials increases the risk of infection. These measures should be prioritized in public health strategies to prevent and control viral gastroenteritis outbreaks.