Effective in vitro inactivation of SARS-CoV- 2 by commercially available mouthwashes

Infectious SARS-CoV- 2 can be recovered from the oral cavities and saliva of COVID-19 patients with potential implications for disease transmission. Reducing viral load in patient saliva using antiviral mouthwashes may therefore have a role as a control measure in limiting virus spread, particularly in dental settings. Here, the efficacy of SARS-CoV- 2 inactivation by seven commercially available mouthwashes with a range of active ingredients were evaluated in vitro. We demonstrate ≥4.1 to ≥5.5 log10 reduction in SARS-CoV- 2 titre following a 1 min treatment with commercially available mouthwashes containing 0.01-0.02 % stabilised hypochlorous acid or 0.58 % povidone iodine, and non-specialist mouthwashes with both alcohol-based and alcohol-free formulations designed for home use. In contrast, products containing 1.5 % hydrogen peroxide or 0.2 % chlorhexidine gluconate were ineffective against SARS-CoV- 2 in these tests. This study contributes to the growing body of evidence surrounding virucidal efficacy of mouthwashes/oral rinses against SARS-CoV- 2, and has important applications in reducing risk associated with aerosol generating procedures in dentistry and potentially for infection control more widely.