Long-Term SARS-CoV-2 Surveillance in the Wastewater of Stockholm: What Lessons Can Be Learned from the Swedish Perspective?
32 Pages Posted: 10 Aug 2022
Abstract
Wastewater-based epidemiology (WBE) can be used to track spread of SARS-CoV-2 in a population. In this study, SARS-CoV-2 was measured from April 2020 until June 2022 (providing information for 104 weeks), and we present the learned lessons of more than two-year-long monitoring. The three main wastewater treatment plants in Stockholm, with a total of six inlets, were monitored and the results spans five main SARS-CoV-2 waves, in each of which WBE data provided early warning signals. The SARS-CoV-2 levels correlated significantly with the positive COVID-19 cases (0.86).During this long-term surveillance, two sampling protocols, two RNA concentration/extraction methods, two calculation approaches, and normalization to the RNA virus Pepper mild mottle virus (PMMoV) are here presented and discussed. A storage condition study was performed, and we demonstrate that decay of virus RNA (Nucleocapsid gene and PMMoV) was lower when glycerol was added to the wastewater before storage at -80°C. Furthermore, as proof-of-concept, six SARS-CoV-2 variants of concern were monitored using hyperplex padlock PCR (hpPCR). Our results can contribute to a greater understanding of the multiple factors affecting SARS-CoV-2 surveillance in wastewater and provide valuable information that can be used in further investigations, by health public agencies to incorporate WBE as a prediction tool for possible future outbreaks of SARS-CoV-2 and in preparations for future pandemics.
Note:
Funding Information: This research was supported by SciLifeLab, Pandemic Laboratory Preparedness, the Knut and Alice Wallenberg Foundation (KAW 2020.0182, 2020.0241), the Region Stockholm, the Swedish Research Council (2017-01658, 2018-06169), WaterCenter@KTH, and the KTH Life Science platform.
Declaration of Interests: All authors declare no competing interests.
Keywords: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), COVID-19, Wastewater-based epidemiology (WBE), Storage conditions, Sewage surveillance, Hyperplex padlock PCR
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