Low Risk of Severe Acute Respiratory Syndrome Coronavirus 2 Transmission by Fomites: A Clinical Observational Study in Highly Infectious Coronavirus Disease 2019 Patients

J Infect Dis. 2022 Nov 1;226(9):1608-1615. doi: 10.1093/infdis/jiac170.

Abstract

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. More importantly, the risk of fomite-based transmission has not been systematically addressed. Therefore, the aim of this study was to evaluate whether confirmed hospitalized coronavirus disease 2019 (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 15 COVID-19 patients with a high baseline viral load (cycle threshold value ≤25). We documented clinical and laboratory parameters and used patient samples to perform virus culture, quantitative polymerase chain reaction, and virus sequencing.

Results: Nasopharyngeal and oropharyngeal swabs of all patients were positive for viral ribonucleic acid on the day of the study. Infectious SARS-CoV-2 could be isolated from 6 patient swabs (46.2%). After coughing, no infectious virus could be recovered, however, 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 it is unlikely to occur in real-life scenarios and from droplet-contaminated fomites.

Keywords: COVID-19; SARS-CoV-2; fomite transmission; surface stability.

Publication types

  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • COVID-19*
  • Communicable Diseases*
  • Fomites
  • Humans
  • Pandemics
  • SARS-CoV-2
  • Viral Load