Virucidal activity and mechanism of action of cetylpyridinium chloride against SARS-CoV-2

OBJECTIVE: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the pathogen causing the coronavirus disease 2019 (COVID-19) global pandemic. Recent studies have shown the importance of the throat and salivary glands as sites of virus replication and transmission. The viral host receptor, angiotensin-converting enzyme 2 (ACE2), is broadly enriched in epithelial cells of the salivary glands and oral mucosae. Oral care products containing cetylpyridinium chloride (CPC) as a bactericidal ingredient are known to exhibit antiviral activity against SARS-CoV-2 in vitro. However, the exact mechanism of action remains unknown. METHODS: This study examined the antiviral activity of CPC against SARS-CoV-2 and its inhibitory effect on the interaction between the viral spike (S) protein and ACE2 using an enzyme-linked immunosorbent assay. RESULTS: CPC (0.05%, 0.1% and 0.3%) effectively inactivated SARS-CoV-2 within the contact times (20 and 60 s) in directions for use of oral care products in vitro. The binding ability of both the S protein and ACE2 were reduced by CPC. CONCLUSIONS: Our results suggest that CPC inhibits the interaction between S protein and ACE2, and thus, reduces infectivity of SARS-CoV-2 and suppresses viral adsorption.