Modeling COVID-19 infection risks for a single hand-to-fomite scenario and potential risk reductions offered by surface disinfection

Summary

• Quantitative microbial risk assessment was used to relate surface disinfection efficacy to COVID-19 infection risk.
• Little log₁₀ reductions may be needed for low viral bioburden conditions.
• >2 log₁₀ may be needed to achieve risks <1:1,000,000 for high viral bioburden.

In this study quantitative microbial risk assessment was used to relate log₁₀ disinfection reductions of SARS-CoV-2 bioburden to COVID-19 infection risks. Under low viral bioburden, minimal log₁₀ reductions may be needed to reduce infection risks for a single hand-to-fomite touch to levels lower than 1:1,000,000, as a risk comparison point. For higher viral bioburden conditions, log₁₀ reductions of more than 2 may be needed to achieve median infection risks of less than 1:1,000,000.

Wilson AM, Weir MH, Bloomfield SF, Scott EA, Reynolds KA. Modeling COVID-19 infection risks for a single hand-to-fomite scenario and potential risk reductions offered by surface disinfection. American journal of infection control. 2020 Nov 15. https://www.ajicjournal.org/article/S0196-6553(20)30997-4/fulltext