Evaluation of virucidal activity of residual quaternary ammonium-treated surfaces on SARS-CoV-2

BACKGROUND: The COVID-19 pandemic has had an unprecedented impact on global health and the world's economies. Proliferation of virulent and deadly SARS-CoV-2 variants require effective transmission mitigation strategies. Under reasonable environmental conditions, culturable and infectious SARS-CoV-2 can survive on contaminated fomites from hours to months. In the present study we evaluated a surface-anchored polymeric quaternary ammonium antimicrobial to help reduce fomite transmission of SARS-CoV-2 from contaminated surfaces. METHODS: Two studies were performed on antimicrobial pre-treated metal disks in March 2020 by two independent Biosafety Level III (BSL-3) equipped laboratories in April 2020. These facilities were in Belgium (the Rega Medical Research Institute) and Australia (the Peter Doherty Institute) and independently applied quantitative carrier-based methodologies using the authentic SARS-CoV-2 isolates (hCoV-19/Australia/VIC01/2020, hCoV-19/Belgium/GHB-03021/2020). RESULTS: Residual dry tests were independently conducted at both facilities and demonstrated sustained virion destruction (108.23 TCID50/carrier GHB-03021 isolate, and 103.66 TCID50/carrier VIC01 isolate) 1 hour (drying) + 10 minutes after inoculation. Reductions are further supported by degradation of RNA on antimicrobial-treated surfaces using qRT-PCR. CONCLUSIONS: Using a polymeric quaternary ammonium antimicrobial (EPA/PMRA registered) the results independently support a sustained antiviral effect via SARS-CoV-2 virion destruction and viral RNA degradation. This indicates that silane-anchored quaternary ammonium compound (SiQAC-18) treated surfaces could play an important role in mitigating the communicability and fomite transmission of SARS-CoV-2.