BACKGROUND: The contribution of droplet-contaminated surfaces for virus transmission has been discussed controversially in the context of the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) pandemic. Importantly, the risk of fomite-based transmission has not been systematically addressed. Therefore, the aim of this study was to evaluate if confirmed hospitalized COVID-19 patients can contaminate stainless steel carriers by coughing or intensive moistening with saliva and to assess the risk of SARS-CoV-2 transmission upon detection of viral loads and infectious virus in cell culture. METHODS: We initiated a single-center observational study including fifteen COVID-19 patients with a high baseline viral load (CT value ≤ 25). We documented clinical and laboratory parameters and used patient samples to perform virus culture, quantitative PCR and virus sequencing. RESULTS: Nasopharyngeal and oropharyngeal swabs of all patients were positive for viral RNA on the day of the study. Infectious SARS-CoV-2 could be isolated from 6 patient swabs (46.2 %). While after coughing, no infectious virus could be recovered, intensive moistening with saliva resulted in successful viral recovery from steel carriers of 5 patients (38.5 %). CONCLUSIONS: Transmission of infectious SARS-CoV-2 via fomites is possible upon extensive moistening, but unlikely to occur in real-life scenarios and from droplet-contaminated fomites.
BACKGROUND: The contribution of droplet-contaminated surfaces for virus transmission has been discussed controversially in the context of the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) pandemic. Importantly, the risk of fomite-based transmission has not been systematically addressed. Therefore, the aim of this study was to evaluate if confirmed hospitalized COVID-19 patients can contaminate stainless steel carriers by coughing or intensive moistening with saliva and to assess the risk of SARS-CoV-2 transmission upon detection of viral loads and infectious virus in cell culture. METHODS: We initiated a single-center observational study including fifteen COVID-19 patients with a high baseline viral load (CT value ≤ 25). We documented clinical and laboratory parameters and used patient samples to perform virus culture, quantitative PCR and virus sequencing. RESULTS: Nasopharyngeal and oropharyngeal swabs of all patients were positive for viral RNA on the day of the study. Infectious SARS-CoV-2 could be isolated from 6 patient swabs (46.2 %). While after coughing, no infectious virus could be recovered, intensive moistening with saliva resulted in successful viral recovery from steel carriers of 5 patients (38.5 %). CONCLUSIONS: Transmission of infectious SARS-CoV-2 via fomites is possible upon extensive moistening, but unlikely to occur in real-life scenarios and from droplet-contaminated fomites.