Pathogens (May 2023)

Wastewater-Based Epidemiology as a Tool to Detect SARS-CoV-2 Circulation at the Community Level: Findings from a One-Year Wastewater Investigation Conducted in Sicily, Italy

  • Carmelo Massimo Maida,
  • Fabio Tramuto,
  • Giovanni Maurizio Giammanco,
  • Roberta Palermo,
  • Walter Priano,
  • Simona De Grazia,
  • Giuseppa Purpari,
  • Giuseppina La Rosa,
  • Elisabetta Suffredini,
  • Luca Lucentini,
  • Mario Palermo,
  • Walter Pollina Addario,
  • Giorgio Graziano,
  • Palmira Immordino,
  • Francesco Vitale,
  • SARI Collaboration Group,
  • Walter Mazzucco

DOI
https://doi.org/10.3390/pathogens12060748
Journal volume & issue
Vol. 12, no. 6
p. 748

Abstract

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Wastewater-based epidemiology is a well-established tool for detecting and monitoring the spread of enteric pathogens and the use of illegal drugs in communities in real time. Since only a few studies in Italy have investigated the correlation between SARS-CoV-2 in wastewater and the prevalence of COVID-19 cases from clinical testing, we conducted a one-year wastewater surveillance study in Sicily to correlate the load of SARS-CoV-2 RNA in wastewater and the reported cumulative prevalence of COVID-19 in 14 cities from October 2021 to September 2022. Furthermore, we investigated the role of SARS-CoV-2 variants and subvariants in the increase in the number of SARS-CoV-2 infections. Our findings showed a significant correlation between SARS-CoV-2 RNA load in wastewater and the number of active cases reported by syndromic surveillance in the population. Moreover, the correlation between SARS-CoV-2 in wastewater and the active cases remained high when a lag of 7 or 14 days was considered. Finally, we attributed the epidemic waves observed to the rapid emergence of the Omicron variant and the BA.4 and BA.5 subvariants. We confirmed the effectiveness of wastewater monitoring as a powerful epidemiological proxy for viral variant spread and an efficient complementary method for surveillance.

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