Tracking the Effects of the COVID-19 Pandemic on Viral Gastroenteritis Through Wastewater-Based Retrospective Analyses

Abstract

The COVID-19 pandemic possibly disrupted the circulation and seasonality of gastroenteritis viruses (e.g., Norovirus (NoV), Sapovirus (SaV), group A rotavirus (ARoV), and Aichivirus (AiV)). Despite the growing application of wastewater-based epidemiology (WBE), there remains a lack of sufficient investigations into the actual impact of the COVID-19 pandemic on the prevalence of gastroenteritis viruses. In this study, we measured NoV GⅠ and GⅡ, SaV, ARoV, and AiV RNA concentrations in 296 influent wastewater samples collected from three WWTPs in Sapporo, Japan between October 28, 2018 and January 12, 2023 using the highly sensitive EPISENSTM method. The detection ratios of SaV and ARoV after May 2020 (SaV: 49.8% (134/269), ARoV: 57.4% (151/263)) were significantly lower than those before April 2020 (SaV: 93.9% (31/33), ARoV: 97.0% (32/33); SaV: p < 3.5 10-7, ARoV: p < 1.5 10-6). Furthermore, despite comparable detection ratios before (88.5%, 23/26) and during (66.7%, 80/120) the COVID-19 pandemic (p= 0.032), the concentrations of NoV GII revealed a significant decrease after the onset of the pandemic (p < 1.5 10-7, Cliff’s delta = 0.72). NoV GⅠ RNA were sporadically detected (24.7%, 8/33) before April 2020 and after May 2020 (6.5%, 17/263), whereas AiV was consistently (100%, 33/33) detected from wastewater throughout the study period (95.8%, 252/263). The WBE results demonstrated the significant influence of COVID-19 countermeasures on the circulation of gastroenteritis viruses, with variations observed in the magnitude of their impact across different types of viruses. These epidemiological findings highlight that the hygiene practices in preventing COVID-19 infections may also be effective in controlling the prevalence of gastroenteritis viruses, providing invaluable insights for public health units for the development of effective disease management guidelines.

Note:
Funding Information: This study was supported by the Japan Science and Technology Agency (JST) through the JST-Mirai Program, under grant number JPMJMI22D1; the Japan Agency for Medical Research and Development (AMED), under grant number JP22fk0108508; Shionogi & Co., Ltd.; and AdvanSentinel, Inc.

Declaration of Interests: Masaaki Kitajima received research funding from Shionogi & Co., Ltd. and AdvanSentinel, Inc. and patent royalties from Shionogi & Co., Ltd. Satoshi Okabe received research funding from Shionogi & Co., Ltd and AdvanSentinel, Inc. Hiroki Ando and Warish Ahmed have no competing interests to declare.

Keywords: Aichivirus, Norovirus, public health intervention, Rotavirus, Sapovirus, wastewater surveillance