Monitoring the Emergence of SARS-CoV-2 VOCs in Wastewater and Clinical Samples—A One-Year Study in Santiago de Compostela (Spain)

Wastewater surveillance has become a valuable tool to monitor the emergence of SARS-CoV-2 variants of concern (VOCs) at the community level. In this study, we aimed to evaluate the presence of Alpha (B.1.1.7), Beta (B.1.351), Delta (B.1617.2), and Omicron (B.1.1.529) VOCs in samples from the inlet o...

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Main Authors: Marta Lois, David Polo, María Luisa Pérez del Molino, Amparo Coira, Antonio Aguilera, Jesús L. Romalde
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Viruses
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Online Access:https://www.mdpi.com/1999-4915/17/4/489
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author Marta Lois
David Polo
María Luisa Pérez del Molino
Amparo Coira
Antonio Aguilera
Jesús L. Romalde
author_facet Marta Lois
David Polo
María Luisa Pérez del Molino
Amparo Coira
Antonio Aguilera
Jesús L. Romalde
author_sort Marta Lois
collection DOAJ
description Wastewater surveillance has become a valuable tool to monitor the emergence of SARS-CoV-2 variants of concern (VOCs) at the community level. In this study, we aimed to evaluate the presence of Alpha (B.1.1.7), Beta (B.1.351), Delta (B.1617.2), and Omicron (B.1.1.529) VOCs in samples from the inlet of a wastewater treatment plant (WWTP) as well as from two different sewer interceptors (SI-1 and SI-2) from the urban sewage system in Santiago de Compostela (Galicia, NW of Spain) throughout 2021 and January 2022. For this purpose, detection and quantification of the four VOCs was performed using four duplex SARS-CoV-2 allelic discrimination RT-qPCR assays, targeting the S-gene. An N1 RT-qPCR gene assay was used as a reference for the presence of SARS-CoV-2 RNA in wastewater samples. All VOCs were detected in wastewater samples. Alpha, Beta, Delta, and Omicron VOCs were detected in 45.7%, 7.5%, 66.7%, and 72.7% of all samples, respectively. Alpha VOC was dominant during the first part of the study, whereas Delta and Omicron detection peaks were observed in May–June and December 2021, respectively. Some differences were observed among the results obtained for the two city sectors studied, which could be explained by the differences in the characteristics of the population between them. Wastewater-based epidemiology allowed us to track the early circulation and emergence of SARS-CoV-2 variants at a local level, and our results are temporally concordant with clinical data and epidemiological findings reported by the health authorities.
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spelling doaj-art-1e974ec844b549e7a1a77e2aa0ba0ff32025-08-20T02:18:01ZengMDPI AGViruses1999-49152025-03-0117448910.3390/v17040489Monitoring the Emergence of SARS-CoV-2 VOCs in Wastewater and Clinical Samples—A One-Year Study in Santiago de Compostela (Spain)Marta Lois0David Polo1María Luisa Pérez del Molino2Amparo Coira3Antonio Aguilera4Jesús L. Romalde5CRETUS, Departament de Microbiología y Parasitología, CIBUS-Faculty de Biología, University de Santiago de Compostela, 15782 Santiago de Compostela, SpainCRETUS, Departament de Microbiología y Parasitología, CIBUS-Faculty de Biología, University de Santiago de Compostela, 15782 Santiago de Compostela, SpainServicio de Microbiología, Hospital Clínico University de Santiago, 15706 Santiago de Compostela, SpainServicio de Microbiología, Hospital Clínico University de Santiago, 15706 Santiago de Compostela, SpainServicio de Microbiología, Hospital Clínico University de Santiago, 15706 Santiago de Compostela, SpainCRETUS, Departament de Microbiología y Parasitología, CIBUS-Faculty de Biología, University de Santiago de Compostela, 15782 Santiago de Compostela, SpainWastewater surveillance has become a valuable tool to monitor the emergence of SARS-CoV-2 variants of concern (VOCs) at the community level. In this study, we aimed to evaluate the presence of Alpha (B.1.1.7), Beta (B.1.351), Delta (B.1617.2), and Omicron (B.1.1.529) VOCs in samples from the inlet of a wastewater treatment plant (WWTP) as well as from two different sewer interceptors (SI-1 and SI-2) from the urban sewage system in Santiago de Compostela (Galicia, NW of Spain) throughout 2021 and January 2022. For this purpose, detection and quantification of the four VOCs was performed using four duplex SARS-CoV-2 allelic discrimination RT-qPCR assays, targeting the S-gene. An N1 RT-qPCR gene assay was used as a reference for the presence of SARS-CoV-2 RNA in wastewater samples. All VOCs were detected in wastewater samples. Alpha, Beta, Delta, and Omicron VOCs were detected in 45.7%, 7.5%, 66.7%, and 72.7% of all samples, respectively. Alpha VOC was dominant during the first part of the study, whereas Delta and Omicron detection peaks were observed in May–June and December 2021, respectively. Some differences were observed among the results obtained for the two city sectors studied, which could be explained by the differences in the characteristics of the population between them. Wastewater-based epidemiology allowed us to track the early circulation and emergence of SARS-CoV-2 variants at a local level, and our results are temporally concordant with clinical data and epidemiological findings reported by the health authorities.https://www.mdpi.com/1999-4915/17/4/489wastewater-based epidemiologyCOVID-19SARS-CoV-2VOCsduplex RT-qPCR
spellingShingle Marta Lois
David Polo
María Luisa Pérez del Molino
Amparo Coira
Antonio Aguilera
Jesús L. Romalde
Monitoring the Emergence of SARS-CoV-2 VOCs in Wastewater and Clinical Samples—A One-Year Study in Santiago de Compostela (Spain)
Viruses
wastewater-based epidemiology
COVID-19
SARS-CoV-2
VOCs
duplex RT-qPCR
title Monitoring the Emergence of SARS-CoV-2 VOCs in Wastewater and Clinical Samples—A One-Year Study in Santiago de Compostela (Spain)
title_full Monitoring the Emergence of SARS-CoV-2 VOCs in Wastewater and Clinical Samples—A One-Year Study in Santiago de Compostela (Spain)
title_fullStr Monitoring the Emergence of SARS-CoV-2 VOCs in Wastewater and Clinical Samples—A One-Year Study in Santiago de Compostela (Spain)
title_full_unstemmed Monitoring the Emergence of SARS-CoV-2 VOCs in Wastewater and Clinical Samples—A One-Year Study in Santiago de Compostela (Spain)
title_short Monitoring the Emergence of SARS-CoV-2 VOCs in Wastewater and Clinical Samples—A One-Year Study in Santiago de Compostela (Spain)
title_sort monitoring the emergence of sars cov 2 vocs in wastewater and clinical samples a one year study in santiago de compostela spain
topic wastewater-based epidemiology
COVID-19
SARS-CoV-2
VOCs
duplex RT-qPCR
url https://www.mdpi.com/1999-4915/17/4/489
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