Abstract

Background:

Positive correlations have been reported between wastewater SARS-CoV-2 concentrations and a community’s burden of infection, disease or both. However, previous studies mostly compared wastewater to clinical case counts or nonrepresentative convenience samples, limiting their quantitative potential.

Objectives:

This study examined whether wastewater SARS-CoV-2 concentrations could provide better estimations for SARS-CoV-2 community prevalence than reported cases of COVID-19. In addition, this study tested whether wastewater-based epidemiology methods could identify neighborhood-level COVID-19 hotspots and SARS-CoV-2 variants.

Methods:

Community SARS-CoV-2 prevalence was estimated from eight randomized door-to-door nasal swab sampling events in six Oregon communities of disparate size, location, and demography over a 10-month period. Simultaneously, wastewater SARS-CoV-2 concentrations were quantified at each community’s wastewater treatment plant and from 22 Newport, Oregon, neighborhoods. SARS-CoV-2 RNA was sequenced from all positive wastewater and nasal swab samples. Clinically reported case counts were obtained from the Oregon Health Authority.

Results:

Estimated community SARS-CoV-2 prevalence ranged from 8 to 1,687/10,000 persons. Community wastewater SARS-CoV-2 concentrations ranged from 2.9 to $5.1{\log }_{10}$ gene copies per liter. Wastewater SARS-CoV-2 concentrations were more highly correlated (Pearson’s $r=0.96$; $R^2=0.91$) with community prevalence than were clinically reported cases of COVID-19 (Pearson’s $r=0.85$; $R^2=0.73$). Monte Carlo simulations indicated that wastewater SARS-CoV-2 concentrations were significantly better than clinically reported cases at estimating prevalence ($p<0.05$). In addition, wastewater analyses determined neighborhood-level COVID-19 hot spots and identified SARS-CoV-2 variants (B.1 and B.1.399) at the neighborhood and city scales.

Discussion:

The greater reliability of wastewater SARS-CoV-2 concentrations over clinically reported case counts was likely due to systematic biases that affect reported case counts, including variations in access to testing and underreporting of asymptomatic cases. With these advantages, combined with scalability and low costs, wastewater-based epidemiology can be a key component in public health surveillance of COVID-19 and other communicable infections. https://doi.org/10.1289/EHP10289

中文翻译：

---

评估基于废水的流行病学方法来估计 SARS-CoV-2 感染的流行率以及在城市和社区范围内俄勒冈州不同社区的病毒变异检测

摘要

背景：

据报道，废水 SARS-CoV-2 浓度与社区感染、疾病或两者的负担之间存在正相关。然而，以前的研究大多将废水与临床病例计数或非代表性便利样本进行比较，从而限制了它们的定量潜力。

目标：

这项研究检查了废水 SARS-CoV-2 浓度是否可以比报告的 COVID-19 病例更好地估计 SARS-CoV-2 社区流行率。此外，这项研究还测试了基于废水的流行病学方法是否可以识别社区级别的 COVID-19 热点和 SARS-CoV-2 变体。

方法：

社区 SARS-CoV-2 流行率是根据 10 个月期间在俄勒冈州大小、位置和人口统计不同的六个社区中的八次随机挨家挨户鼻拭子采样事件估算的。同时，在每个社区的废水处理厂和俄勒冈州纽波特市的 22 个社区对废水 SARS-CoV-2 浓度进行了量化。从所有阳性废水和鼻拭子样本中对 SARS-CoV-2 RNA 进行了测序。临床报告的病例数来自俄勒冈州卫生局。

结果：

估计的社区 SARS-CoV-2 流行率为 8 至 1,687/10,000 人。社区废水 SARS-CoV-2 浓度范围为 2.9 至$5.1{\mathrm{日志}}_{10}$每升基因拷贝数。废水 SARS-CoV-2 浓度的相关性更高（Pearson's$r=0.96$;$R^2=0.91$) 的社区患病率高于临床报告的 COVID-19 病例 (Pearson's$r=0.85$;$R^2=0.73$）。蒙特卡罗模拟表明，在估计患病率时，废水 SARS-CoV-2 的浓度明显优于临床报告的病例。$p<0.05$）。此外，废水分析确定了社区级别的 COVID-19 热点，并确定了社区和城市规模的 SARS-CoV-2 变体（B.1 和 B.1.399）。

讨论：

与临床报告病例数相比，废水 SARS-CoV-2 浓度的更高可靠性可能是由于影响报告病例数的系统性偏差，包括检测机会的变化和无症状病例的少报。凭借这些优势，再加上可扩展性和低成本，基于废水的流行病学可以成为 COVID-19 和其他传染性感染的公共卫生监测的关键组成部分。https://doi.org/10.1289/EHP10289