Abstract: pathogens Article Differential Effects of Antiseptic Mouth Rinses on SARS-CoV-2 Infectivity In Vitro Chuan Xu 1 , Annie Wang 1 , Eileen R. Hoskin 2 , Carla Cugini 3 , Kenneth Markowitz 3 , Theresa L. Chang 1,4, * and Daniel H. Fine 3, * 1 2 3 4 *



 Citation: Xu, C.; Wang, A.; Hoskin, E.R.; Cugini, C.; Markowitz, K.; Chang, T.L.; Fine, D.H. Differential Effects of Antiseptic Mouth Rinses on SARS-CoV-2 Infectivity In Vitro. Pathogens 2021, 10, 272. https:// doi.org/10.3390/pathogens10030272 Academic Editor: Sonia Zuñiga Received: 1 February 2021 Accepted: 22 February 2021 Published: 1 March 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- Public Health Research Institute, Rutgers, New Jersey Medical School, 225 Warren Street, Newark, NJ 07103, USA; cx89@njms.rutgers.edu (C.X.); aw768@njms.rutgers.edu (A.W.) Department of Restorative Dentistry, School of Dental Medicine, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA; hoskiner@sdm.rutgers.edu Department of Oral Biology, School of Dental Medicine, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA; cc1337@sdm.rutgers.edu (C.C.); markowkj@sdm.rutgers.edu (K.M.) Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA Correspondence: theresa.chang@rutgers.edu (T.L.C.); finedh@sdm.rutgers.edu (D.H.F.); Tel.: +1-973-854-3265 (T.L.C.); +1-973-972-3728 (D.H.F.); Fax: +1-973-854-3101 (T.L.C.); +1-973-972-0045 (D.H.F.) Abstract: Severe acute respiratory syndrome-related coronavirus (SARS-CoV-2) is detectable in saliva from asymptomatic individuals, suggesting a potential benefit from the use of mouth rinses to suppress viral load and reduce virus spread. Published studies on the reduction of SARS-CoV-2-induced cytotoxic effects by mouth rinses do not exclude antiseptic mouth rinse-associated cytotoxicity. Here, we determined the effect of commercially available mouth rinses and antiseptic povidone-iodine on the infectivity of replication-competent SARS-CoV-2 viruses and of pseudotyped SARS-CoV-2 viruses. We first determined the effect of mouth rinses on cell viability to ensure that antiviral activity was not a consequence of mouth rinse-induced cytotoxicity. Colgate Peroxyl (hydrogen peroxide) exhibited the most cytotoxicity, followed by povidone-iodine, chlorhexidine gluconate (CHG), and Listerine (essential oils and alcohol). The potent antiviral activities of Colgate Peroxyl mouth rinse and povidone-iodine were the consequence of rinse-mediated cellular damage when the products were present during infection. The potency of CHG was greater when the product was not washed off after virus attachment, suggesting that the prolonged effect of mouth rinses on cells impacts the antiviral outcome. To minimalize mouth rinse-associated cytotoxicity, mouth rinse was largely removed from treated viruses by centrifugation prior to infection of cells. A 5% (v/v) dilution of Colgate Peroxyl or povidone-iodine completely blocked viral infectivity. A similar 5% (v/v) dilution of Listerine or CHG had a moderate suppressive effect on the virus, but a 50% (v/v) dilution of Listerine or CHG blocked viral infectivity completely. Mouth rinses inactivated the virus without prolonged incubation. The new infectivity assay, with limited impacts of mouth rinse-associated cytotoxicity,..