Stability of Human Coronavirus OC43 on Leather and Viral Transfer to Different Surfaces

Aims: This study aimed to investigate the stability of HCoV-OC43 on leather and transfer to other surfaces and to determine the antiviral activity of a silver-based leather coating.

Methods and Results: The infectivity of HCoV-OC43 (6.6 log10 TCID50) on patent, nubuck, full-grain calf and corrected grain leathers (untreated and silver-coated) was measured over 72 hours by titration on BHK-21 cells. Recovery from pig skin (8-9 log10 TCID50) was also assessed. Transfer of infectious HCoV-OC43 from leather onto cardboard and stainless steel (0-48 hours post-inoculation) was quantified. HCoV-OC43 remained infectious for 6-48 hours on patent, finished and calf leathers; no infectious HCoV-OC43 was recovered from nubuck at 0 hours. Silver coating of full-grain calf and corrected grain leathers significantly reduced HCoV-OC43 infectivity (p≤0.05) after 2 hours, where no infectious virus was recovered. Transfer of HCoV-OC43 (≤3.1-5.5 log10) was detected from calf, finished and patent leather onto stainless steel and carboard up to 2 hours after inoculation, while no transfer was detected for silver-coated leathers at 2 hours. Leather has also been utilised as a skin surrogate for investigating fomite transmission. HCoV-OC43 was reduced by 4.71 log10 on pig skin at 0 hours, in a similar trend to highly absorbent nubuck leather. Conclusions: Human coronaviruses remain infectious on leather for up to 48 hours and transfer onto cardboard and stainless steel up to 2 hours post-inoculation. Absorbency contributes to the recovery/persistence of HCoV-OC43 on surfaces. A silver-based leather coating demonstrated antiviral activity and limited viral transfer onto other surfaces.

Significance of Study: This investigation suggests that leather could pose a risk of indirect transmission of human coronaviruses; this is of significance for settings where there is close contact with leathers such as in manufacturing, retail and domestic environments. A silver-based leather coating demonstrated antiviral activity and limited viral transfer onto other surfaces, reducing the potential for indirect transmission from leathers.