Highly predictive regression model of active cases of COVID-19 in a population by screening wastewater viral load

Abstract

The quantification of the SARS-CoV-2 load in wastewater has emerged as a useful method to monitor COVID-19 outbreaks in the community. This approach was implemented in the metropolitan area of A Coruña (NW Spain), where wastewater from the treatment plant of Bens was analyzed to track the epidemic’s dynamic in a population of 369,098 inhabitants. We developed statistical regression models that allowed us to estimate the number of infected people from the viral load detected in the wastewater with a reliability close to 90%. This is the first wastewater-based epidemiological model that could potentially be adapted to track the evolution of the COVID-19 epidemic anywhere in the world, monitoring both symptomatic and asymptomatic individuals. It can help to understand with a high degree of reliability the true magnitude of the epidemic in a place at any given time and can be used as an effective early warning tool for predicting outbreaks.

Occurrence of various viruses and recent evidence of SARS-CoV-2 in wastewater systems

“…In addition, starting on April 19 th , 24-hour composite wastewater samples were continually analysed until early June, and surveillance will continue at the Bens WWTP until the viral genetic material disappears. The results of this study identified a decrease in COVID-19 incidence and further confirmed that the time course of the quantifiable discovery of SARS-CoV-2 in wastewater was inversely correlated with the number of confirmed COVID-19 cases ( Vallejo et al, 2020 ).…”

“…A meta-analysis confirmed that approximately 15% of COVID-19 patients experienced mostly intestinal symptoms and that approximately 10% of patients had intestinal symptoms but not respiratory symptoms ( Ali et al, 2020 ). Correspondingly, SARS-CoV-2 RNA was frequently detected in the faeces of COVID-19 patients who did not experience intestinal symptoms ( Vallejo et al, 2020 , Yeo et al, 2020 ). Several studies reported that approximately 53.9% of patients were positive for faecal viral RNA ( Vallejo et al, 2020 ), and some studies indicated that viruses were excreted in significant amounts in the patients’ stools for an extended period of time ( Chen et al, 2020 ); moreover, in a few cases, the individual was confirmed to be negative based on respiratory samples after a month or more ( Vallejo et al, 2020 , Wölfel et al, 2020 ).…”

“…Furthermore, a study conducted by Vallejo et al applied a wastewater detection approach in the urban area of A Coruña (Spain) with the key objective of developing novel statistical regression models that could be used to assess the dynamics of the COVID-19 epidemic among the population of 369,098. The results of the regression models suggested that the real number of individuals infected with COVID-19 was determined with a reliability of approximately 90% ( Vallejo et al, 2020 ).…”

“…Nevertheless, despite various studies showing that transmission of the virus can occur via the faecal-oral axis ( Ding and Liang, 2020 , Vallejo et al, 2020 ), inadequate evidence is available to confirm this route of transmission ( Vallejo et al, 2020 , Ronchi et al, 2020 ). Moreover, no evidence is available to demonstrate infection via wastewater, which might lead to uncertainty regarding the presence of SARS-CoV-2 in wastewater systems ( Cha et al, 2020 , Chin et al, 2020 , Yeo et al, 2020 ).…”

Catching a resurgence: Increase in SARS-CoV-2 viral RNA identified in wastewater 48 hours before COVID-19 clinical tests and 96 hours before hospitalizations

“…As WBE initiatives rely on the fecally shed viral particles (Collivignarelli et al, 2020; Lodder and de Roda Husman, 2020), an understanding of the predictive ability of this epidemiological metric is necessary for public health units to appropriately action this tool (Hart and Halden, 2020; Hill et al, 2020; Thompson et al, 2020). In particular, studies to date that demonstrate the potential for WBE to identify the onset of community infection prior to clinical testing have largely been applied to identifying first wave of the disease in community (Kaplan et al, 2020; La Rosa et al, 2020; Medema et al, 2020; Nemudryi et al, 2020; Peccia et al, 2020; Sherchan et al, 2020; Vallejo et al, 2020; Wu et al, 2020). Due to limited clinical testing in many countries during the onset of COVID-19 and limited use of wastewater-based SARS-CoV-2 surveillance, it remains unclear whether WBE can have a role in identifying COVID-19 resurgences.…”