Sci Total Environ . Long-term SARS-CoV-2 surveillance in the wastewater of Stockholm: What lessons can be learned from the Swedish perspective?

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Sci Total Environ


. 2022 Nov 7;160023.
doi: 10.1016/j.scitotenv.2022.160023. Online ahead of print.
Long-term SARS-CoV-2 surveillance in the wastewater of Stockholm: What lessons can be learned from the Swedish perspective?


Mariel Perez-Zabaleta ¹ , Amena Archer ² , Kasra Khatami ¹ , Mohammed Hakim Jafferali ² , Prachi Nandy ³ , Merve Atasoy ³ , Madeleine Birgersson ² , Cecilia Williams ² , Zeynep Cetecioglu ⁴



Affiliations

• PMID: 36356735
• DOI: 10.1016/j.scitotenv.2022.160023

Abstract

Wastewater-based epidemiology (WBE) can be used to track the spread of SARS-CoV-2 in a population. This study presents the learning outcomes from over two-year long monitoring of SARS-CoV-2 in Stockholm, Sweden. The three main wastewater treatment plants in Stockholm, with a total of six inlets, were monitored from April 2020 until June 2022 (in total 600 samples). This spans five major SARS-CoV-2 waves, where WBE data provided early warning signals for each wave. Further, the measured SARS-CoV-2 content in the wastewater correlated significantly with the level of positive COVID-19 tests (r = 0.86; p << 0.0001) measured by widespread testing of the population. Moreover, as a proof-of-concept, six SARS-CoV-2 variants of concern were monitored using hpPCR assay, demonstrating that variants can be traced through wastewater monitoring. 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) were evaluated. In addition, a study of storage conditions was performed, demonstrating that the decay of viral RNA was significantly reduced upon the addition of glycerol to the wastewater before storage at -80 °C. Our results provide valuable information that can facilitate the incorporation of WBE as a prediction tool for possible future outbreaks of SARS-CoV-2 and in preparations for future pandemics.

Keywords: COVID-19; Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); Sewage surveillance; Storage conditions; Wastewater-based epidemiology (WBE); hpPCR.