ABSTRACT
Several reviews and models have suggested that indirect contact transmission involving contaminated surfaces could be the predominant transmission route for certain respiratory viruses. Indeed, contaminated environmental surfaces are considered to represent a significant vector for hospital-acquired viral infections. For any environmental contamination to be relevant, a virus should not only remain infectious on the recipient surface but also persist at a sufficient concentration to enable it to reach the respiratory tract via finger contamination. In general terms, the potential of a fomite to spread a given infectious agent is directly related to the capacity of the agent to survive on that surface. The surface stability of viruses is generally influenced by the type of surface, environmental factors such as relative humidity and temperature, and the presence of body fluid secretions (respiratory excretions, feces, blood.). We investigated the influence of such parameters on the stability of several alpha and betacoronaviruses, including 3 variants of SARS-CoV-2 (SARS-CoV-2 variant 2020, SARS-CoV-2 variant UK and SARS-CoV2 variant delta), on stainless steel discs and porous surface corresponding to borosilicate discs. Assays were done at 7 °C and 25 °C with a relative humidity of 65%. Artificial mucus/saliva or BSA/yeast extract mixtures were used as fluid mimetics for respiratory and enteric viruses, respectively. Our results showed significant variable stability of the viruses depending on both the porous/non-porous nature of the surfaces and the temperature. Beneficial or negative impacts of the body fluids were also observed. This study characterizes for the first time the behaviour of human and animal coronaviruses, including highly pathogenic betacoronaviruses, on several surfaces with fixed environmental parameters.