A portion of those infected with SARS-CoV-2 shed the virus and its genetic material in respiratory fluids, saliva, urine, and stool, thus giving the potential to monitor for infections via wastewater. Wastewater surveillance efforts to date have largely assumed that stool shedding has been the primary source of SARS-CoV-2 RNA signal; however, there are increasing questions about the possible contribution of other shedding routes, with implications for wastewater surveillance design and feasibility. In this study we used clinical SARS-CoV-2 RNA shedding data and a Monte Carlo framework to assess the relative contribution of various shedding routes on SARS-CoV-2 RNA loads in wastewater. Stool shedding dominated total SARS-CoV-2 RNA load for community-level surveillance, with mean contributions more than two orders of magnitude greater than other shedding routes. However, RNA loads were more nuanced when considering building-level monitoring efforts designed to identify a single infected individual, where any shedding route could plausibly contribute a detectable signal. The greatest source of model variability was viral load in excreta, suggesting that future modeling efforts may be improved by incorporating specific modeling scenarios with precise SARS-CoV-2 shedding data, and beyond that wastewater surveillance must continue to account for large variability during data analysis and reporting. Importantly, the findings imply that wastewater surveillance at finer spatial scales is not entirely dependent on shedding via feces for sensitive detection of infections thus enlarging the potential use cases of wastewater as a non-intrusive surveillance methodology.

一部分感染了 SARS-CoV-2 的人会在呼吸液、唾液、尿液和粪便中排出病毒及其遗传物质，从而有可能通过废水监测感染情况。迄今为止的废水监测工作在很大程度上假设粪便脱落是 SARS-CoV-2 RNA 信号的主要来源；然而，越来越多的人质疑其他排放路线的可能贡献，并对废水监测设计和可行性产生影响。在这项研究中，我们使用临床 SARS-CoV-2 RNA 脱落数据和蒙特卡罗框架来评估各种脱落途径对废水中 SARS-CoV-2 RNA 负荷的相对贡献。大便脱落主导了社区级监测的 SARS-CoV-2 RNA 总载量，平均贡献比其他脱落路线大两个数量级以上。然而，在考虑旨在识别单个受感染个体的建筑物级监测工作时，RNA 负载更加微妙，其中任何脱落路线都可能提供可检测的信号。模型可变性的最大来源是排泄物中的病毒载量，这表明未来的建模工作可以通过将特定的建模场景与精确的 SARS-CoV-2 排放数据结合起来来改进，除此之外，废水监测必须继续考虑数据分析过程中的巨大可变性和报告。重要的，