Monitoring COVID-19 Transmission Risks by Quantitative Real-Time PCR Tracing of Droplets in Hospital and Living Environments
Andrea Piana, Maria Eugenia Colucci, Federica Valeriani, Adriano Marcolongo, Giovanni Sotgiu, Cesira Pasquarella, Lory Marika Margarucci, Andrea Petrucca, Gianluca Gianfranceschi, Sergio Babudieri, Pietro Vitali, Giuseppe D’Ermo, Assunta Bizzarro, Flavio De Maio, Matteo Vitali, Antonio Azara, Ferdinando Romano, Maurizio Simmaco, Vincenzo Romano Spica
Abstract
Several studies have evaluated the presence of SARS-CoV-2 in the environment. Saliva and nasopharyngeal droplets can land on objects and surfaces, creating fomites. A suitable indicator would allow the detection of droplets or biofluids carrying the virus. Therefore, we searched for viral RNA and droplets and fomites on at risk surfaces. We monitored by qPCR or next generation sequencing (NGS) droplets through their microbiota. Although the study was performed during the pandemic, SARS-CoV-2 was not significantly found on surfaces, with the only exception of environmental areas near infectious patients. Conversely, anthropic contamination was frequent, suggesting a role for biofluids as putative markers of indirect transmission and risk assessment. Moreover, all SARS-CoV-2-contaminated surfaces showed droplets' microbiota. Fomite monitoring by qPCR may have an impact on public health strategies, supporting prevention of indirect transmission similarly to what is done for other communicable diseases (e.g., influenza and influenza-like infections).