Role of interfering substances in the survival of coronaviruses on surfaces and their impact on the efficiency of hand and surface disinfection

Contaminated environmental surfaces are considered to represent a significant vector for hospital-acquired viral infections. In this study, we have evaluated the impact of interfering substances on SARS-CoV-2 surface stability and virucidal efficiency of hand sanitizers and surface disinfectant. To this end, surface stability of SARS-CoV-2 was measured on stainless steel in different experimental conditions, with or without an artificial mucus/saliva mixture and compared against that of human coronavirus HCoV-229E and feline coronavirus FCoV. The impact of the mucus/saliva mixture on the virucidal efficiency of 3 commercial alcohol hand sanitizers and 1 surface chemical disinfectant against SARS-CoV-2, HCoV-229E and FCoV was then measured. Our results indicate that mucus/saliva mixture did not demonstrate a beneficial effect on the surface survival of tested viruses, with temperature being an important parameter. In addition, we demonstrated that interfering substances may play an important role in the virucidal efficacy of hand sanitizers and disinfectants, highlighting the need for adapted testing protocols that better reflect current “real life” conditions of use. Highlights Contaminated environmental surfaces are a significant vector for viral infections. We studied the impact of interfering substances on SARS-CoV-2 surface stability and virucidal efficiency. Mucus/saliva did not demonstrate a beneficial effect on viral surface stability, with temperature being an important parameter. Interfering substances are important for virucidal surface activity of disinfectants.