Virucidal potential of oral rinses and nasal sprays against SARS-COV-2 and their mode of action

Introduction: The ongoing SARS-CoV-2 pandemic creates a significant threat to global health. Recent studies suggested the significance of throat and salivary glands as major sites of virus replication and transmission during early COVID-19 thus advocating application of oral antiseptics. Objectives: Here, we evaluated the virucidal activity of different available oral rinses, nasal sprays as well as individual compounds found in oral rinses against SARS-CoV-2. These experiments were performed under conditions mimicking nasopharyngeal secretions and investigated their respective virucidal modes of action. Methods: According to European guidelines, virucidal activity was determined with a quantitative suspension test with 30 s exposure time on VeroE6 cells. Mechanistic analysis to reveal the mode of action of antiseptic agents included density gradient centrifugation and a capsid protection assay. Results: Three of the eight oral rinses as well as two nasal sprays significantly reduced viral infectivity to up to three orders of magnitude to background levels. Mechanistic analysis revealed that treatment with benzalconiumchloride and other antiseptic agents used in mouth rinses primarily disrupted the viral envelope, without affecting viral RNA integrity. Conclusion: In summary, we provide evidence that SARS-CoV-2 can be efficiently inactivated by commercially available oral rinses and nasal sprays with respect to their compound composition, within short exposure times, thus possibly lowering the transmission of SARS-CoV-2.