Low risk of SARS-CoV-2 transmission by fomites in real-life conditions
Authors: Mario U Mondelli, Marta Colaneri, Elena M Seminari, Fausto Baldanti, Raffaele Bruno
Journal: The Lancet Infectious Diseases (2020)

We read with interest the Comment by Emanuel Goldman1Goldman E Exaggerated risk of transmission of COVID-19 by fomites.Lancet Infect Dis. 2020; (published online July 3.)https://doi.org/10.1016/S1473-3099(20)30561-2Summary Full Text Full Text PDF PubMed Scopus (271) Google Scholar highlighting experiments done under controlled laboratory conditions that suggest persistence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on inanimate surfaces for days, with potential implications for viral transmission.2van Doremalen N Bushmaker T Morris DH et al.Aerosol and surface stability of SARS-CoV-2 as compared with SARS-CoV-1.N Engl J Med. 2020; 382: 1564-1567Crossref PubMed Scopus (6699) Google Scholar Yet, at the same time, Goldman laments the absence of real-life studies investigating the infectious potential of SARS-CoV-2 on contaminated inanimate material and patient fomites, particularly in high-risk hospital wards. A study done in a hospital environment showed that most surfaces were contaminated, including air-conditioning vents, bed rails, bedside lockers, and rarely, toilets.3Chia PY Coleman KK Tan YK et al.Detection of air and surface contamination by SARS-CoV-2 in hospital rooms of infected patients.Nat Commun. 2020; 112800Crossref Scopus (610) Google Scholar Of note, environmental surface contamination declined after week 1 of illness, and intriguingly, no surface contamination was detected in intensive care unit (ICU) rooms. A limitation of the study by Chia and colleagues3Chia PY Coleman KK Tan YK et al.Detection of air and surface contamination by SARS-CoV-2 in hospital rooms of infected patients.Nat Commun. 2020; 112800Crossref Scopus (610) Google Scholar is that no attempt was made to culture SARS-CoV-2 from the environmental swabs, which would have helped to understand the significance of SARS-CoV-2 RNA positive samples in terms of infectious potential. We have done two sequential studies4Colaneri M Seminari E Piralla A et al.Lack of SARS-CoV-2 RNA environmental contamination in a tertiary referral hospital for infectious diseases in Northern Italy.J Hosp Infect. 2020; 105: 474-476Summary Full Text Full Text PDF Scopus (51) Google Scholar, 5Colaneri M Seminari E Novati S et al.Severe acute respiratory syndrome coronavirus 2 RNA contamination of inanimate surfaces and virus viability in a health care emergency unit.Clin Microbiol Infect. 2020; 26: 1094.e1-1094.e5Summary Full Text Full Text PDF Scopus (110) Google Scholar seeking to determine on one hand the extent, if any, of contamination of inanimate surfaces in a standard infectious disease ward of a major referral hospital in northern Italy, and on the other hand whether the risk of contamination was higher in emergency rooms and sub-intensive care wards than on ordinary wards. Cleaning procedures were standard. A number of objects and surfaces were swabbed. Remarkably, only the continuous positive airway pressure helmet of one patient was positive for SARS-CoV-2 RNA. More importantly, attempts to culture the positive swabs on Vero E6 cells were unsuccessful,5Colaneri M Seminari E Novati S et al.Severe acute respiratory syndrome coronavirus 2 RNA contamination of inanimate surfaces and virus viability in a health care emergency unit.Clin Microbiol Infect. 2020; 26: 1094.e1-1094.e5Summary Full Text Full Text PDF Scopus (110) Google Scholar suggesting that patient fomites and surfaces are not contaminated with viable virus. Our findings suggest that environmental contamination leading to SARS-CoV-2 transmission is unlikely to occur in real-life conditions, provided that standard cleaning procedures and precautions are enforced. These data would support Goldman's point that the chance of transmission through inanimate surfaces is less frequent than hitherto recognised. We declare no competing interests. Exaggerated risk of transmission of COVID-19 by fomitesA clinically significant risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission by fomites (inanimate surfaces or objects) has been assumed on the basis of studies that have little resemblance to real-life scenarios. Full-Text PDF