CPC- containing oral rinses inactivate SARS- CoV-2 variants and are active in the presence of human saliva

Introduction. The importance of human saliva in aerosol -based transmission of SARS- CoV- 2 is now widely recognized. However, little is known about the efficacy of virucidal mouthwash formulations against emergent SARS- CoV- 2 variants of concern and in the presence of saliva. Hypothesis. Mouthwashes containing virucidal actives will have similar inactivation effects against multiple SARS- CoV- 2 variants of concern and will retain efficacy in the presence of human saliva. Aim. To examine in vitro efficacy of mouthwash formulations to inactivate SARS- CoV- 2 variants. Methodology. Inactivation of SARS- CoV- 2 variants by mouthwash formulations in the presence or absence of human saliva was assayed using ASTM International Standard E1052-20 methodology. Results. Appropriately formulated mouthwashes containing 0.07 % cetylpyridinium chloride but not 0.2 % chlorhexidine com-pletely inactivated SARS- CoV- 2 (USA- WA1/2020, Alpha, Beta, Gamma, Delta) up to the limit of detection in suspension assays. Tests using USA- WA1/2020 indicates that efficacy is maintained in the presence of human saliva. Conclusions. Together these data suggest cetylpyridinium chloride- based mouthwashes are effective at inactivating SARS-CoV- 2 variants. This indicates potential to reduce viral load in the oral cavity and mitigate transmission via salivary aerosols.