Wastewater-based epidemiology for early warning of SARS-COV-2 circulation: A pilot study conducted in Sicily, Italy
Carmelo Massimo Maida, Emanuele Amodio, Walter Mazzucco, Giuseppina La Rosa, Luca Lucentini, Elisabetta Suffredini, Mario Palermo, Gina Andolina, Francesca Rita Iaia, F. Merlo, Massimo Giuseppe Chiarelli, Angelo Siragusa, Francesco Vitale, Fabio Tramuto, Daniela Segreto, Pietro Schembri, Giuseppe Cuffari, Antonio Conti, Giovanni Casamassima, Andrea Polizzi, Mansueta Ferrara, Giuseppina Gullo, Angelo Lo Verde, Arianna Russo, Alessandra Casuccio, Claudio Costantino, Vincenzo Restivo, Palmira Immordino, Giorgio Graziano
Abstract
There is increasing evidence of the use of wastewater-based epidemiology to integrate conventional monitoring assessing disease symptoms and signs of viruses in a specific territory. We present the results of SARS-CoV-2 environmental surveillance activity in wastewater samples collected between September 2020 and July 2021 in 9 wastewater treatment plants (WTPs) located in central and western Sicily, serving over 570,000 residents. The presence of SARS-CoV-2, determined in 206 wastewater samples using RT-qPCR assays, was correlated with the notified and geo-referenced cases on the areas served by the WTPs in the same study period. Overall, 51% of wastewater samples were positive. Samples were correlated with 33,807 SARS-CoV-2 cases, reported in 4 epidemic waves, with a cumulative prevalence of 5.9% among Sicilian residents. The results suggest that the daily prevalence of SARS-CoV-2 active cases was statistically significant and higher in areas with SARS-CoV-2 positive wastewater samples. According to these findings, the proposed method achieves a good sensitivity profile (78.3%) in areas with moderate or high viral circulation (≥133 cases/100,000 residents) and may represent a useful tool in the management of epidemics based on an environmental approach, although it is necessary to improve the accuracy of the process.