Evaluation of Residual Infectivity after SARS-CoV-2 Aerosol Transmission in a Controlled Laboratory Setting

Luisa Zupin, Sabina Licen, Margherita Milani, Libera Clemente, Lorenzo Martello, Sabrina Semeraro, Francesco Fontana, Maurizio Ruscio, Alessandro Miani, Sergio Crovella and Pierluigi Barbieri
Additional contact information
Luisa Zupin: Institute for Maternal and Child Health, IRCCS Burlo Garofolo, Via dell’Istria 65/1, 34137 Trieste, Italy
Sabina Licen: Department of Chemical and Pharmaceutical Sciences, University of Trieste, Via L. Giorgieri 1, 34127 Trieste, Italy
Margherita Milani: Department of Medicine, Surgery and Health Sciences, University of Trieste, Strada di Fiume 447, 34137 Trieste, Italy
Libera Clemente: Ospedale San Polo, Azienda Sanitaria Universitaria Giuliano Isontina, Via Luigi Galvani 1, 34074 Monfalcone, Italy
Lorenzo Martello: Department of Chemical and Pharmaceutical Sciences, University of Trieste, Via L. Giorgieri 1, 34127 Trieste, Italy
Sabrina Semeraro: INSTM National Interuniversity Consortium of Materials Science and Technology, Via G. Giusti 9, 50121 Firenze, Italy
Francesco Fontana: Ospedale San Polo, Azienda Sanitaria Universitaria Giuliano Isontina, Via Luigi Galvani 1, 34074 Monfalcone, Italy
Maurizio Ruscio: Ospedale Maggiore, Azienda Sanitaria Universitaria Giuliano Isontina, Piazza dell’Ospitale 1, 34129 Trieste, Italy
Alessandro Miani: Department of Environmental Science and Policy, University of Milan, Via Festa del Perdono 7, 20122 Milano, Italy
Sergio Crovella: Department of Biological and Environmental Sciences, College of Arts and Sciences, University of Qatar, Doha 2713, Qatar
Pierluigi Barbieri: Department of Chemical and Pharmaceutical Sciences, University of Trieste, Via L. Giorgieri 1, 34127 Trieste, Italy

IJERPH, 2021, vol. 18, issue 21, 1-14

Abstract: Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) is mainly transmitted through respiratory droplets, aerosols, or direct contact with fomites from an infected subject. It has been reported that SARS-CoV-2 is stable and viable in aerosol up to 16 h in controlled laboratory conditions. However, the aerosolization conditions varied a lot between the studies. In this work, an experimental laboratory model of SARS-CoV-2 aerosolization was established, employing an impinger nebulizer, a cylindrical chamber for aerosol travel, and a SKC biosampler for the collection of particles. The efficiency of the system was assessed based on the molecular determination of the viral load in the nebulizer after the aerosolization and in the aerosol collected at the end of the travel. Moreover, the residual infectivity was tested in vitro on the Vero E6 cell line, through the observation of the cytopathic effect (CPE), and the quantification of the viral load in the supernatants at 7 days post inoculation (dpi). A high RNA viral load was found in the SKC biosampler after aerosolization, indicating that it was possible to transport a high virus titer through the 30-cm chamber with all the dilutions (initial 10 5 , 10 4 , 10 3 plaque forming unit—PFU/mL). At the 7 dpi, an increment of the RNA viral load was determined for the dilutions 10 5 and 10 4 PFU/mL tested, while only the initial 10 5 PFU/mL resulted in visible CPE. Our findings allowed us to achieve the resilience of SARS-CoV-2 in aerosol form, at a concentration comparable to those reported for clinical samples. This mode of transmission should be considered for the mitigation and preventive measures to counteract SARS-CoV-2 spreading.

Keywords: SARS-CoV-2; aerosol; residual infectivity (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2021
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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