Human respiratory viruses, including SARS-CoV-2, circulating in the winter season 2019-2020 in Parma, Northern Italy

Calderaro, Adriana; De Conto, Flora; Buttrini, Mirko; Piccolo, Giovanna; Montecchini, Sara; Maccari, Clara; Martinelli, Monica; Di Maio, Alan; Ferraglia, Francesca; Pinardi, Federica; Montagna, Paolo; Arcangeletti, Maria Cristina; Chezzi, Carlo

OBJECTIVES: This study aimed to determine the prevalence of respiratory virus infections, including SARS-CoV-2, during December 2019 – March 2020, in a tertiary care hospital-based survey in Parma (Northern Italy). METHODS: A total of 906 biological samples of respiratory tract were analyzed by both conventional (including culture) and molecular assays targeting SARS-CoV-2 and the other respiratory viruses nucleic acids. RESULTS: 474 samples (52.3%) were positive for at least one virus for a total of 583 viruses detected. Single infections were detected in 380 (80.2%) samples and mixed infections were detected in 94 (19.8%). RSV (138/583: 23.7%) and RV (130/583: 22.3%) were the most common viruses identified, followed by SARS-CoV2 (82/583: 14.1%). RSV predominates until February with 129 detections and drastically decreases in March to 9 detections. SARS-CoV-2 absent in our area until February 26, in just over a month reached 82 detections. SARS-CoV-2 was found in mixed infections only in 3 cases all observed in children younger than one year old. CONCLUSIONS: This study showed a completely different trend between SARS-CoV-2 and the "common" respiratory viruses that have seen children most affected without distinction of sex, as opposed to SARS-CoV-2 that have seen adult males the most infected.