Virucidal Efficacy of Different Oral Rinses Against Severe Acute Respiratory Syndrome Coronavirus 2

Abstract: The Journal of Infectious Diseases BRIEF REPORT Virucidal Efficacy of Different Oral Rinses Against Severe Acute Respiratory Syndrome Coronavirus 2 Toni Luise Meister,1 Yannick Brüggemann,1 Daniel Todt,1,2 Carina Conzelmann,3 Janis A. Müller,3 Rüdiger Groß,3 Jan Münch,3 Adalbert Krawczyk,4,5 Jörg Steinmann,6,7 Jochen Steinmann,8 Stephanie Pfaender,1,a and Eike Steinmann1,a The ongoing severe acute respiratory syndrome coronavirus 2 (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 coronavirus disease 2019, thus advocating application of oral antiseptics. However, the antiviral efficacy of oral rinsing solutions against SARS-CoV-2 has not been examined. Here, we evaluated the virucidal activity of different available oral rinses against SARS-CoV-2 under conditions mimicking nasopharyngeal secretions. Several formulations with significant SARS-CoV-2 inactivating properties in vitro support the idea that oral rinsing might reduce the viral load of saliva and could thus lower the transmission of SARS-CoV-2. Keywords. SARS-CoV-2; oral rinses; inactivation; suspension test; transmission. The current severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has created a significant threat to global health. Since effective treatments and vaccines are currently not available, diligent attention on transmission-based precautions is essential to limit viral spread. According to current evidence, SARS-CoV-2 is mainly transmitted through respiratory droplets exhaled from infected individuals [1]. Importantly, viral loads are high in the nasal cavity, nasopharynx, and oropharynx and viral shedding can be detected before, during, and after the acute clinical phase of illness [2]. Aerosols produced Received 18 June 2020; editorial decision 21 July 2020; accepted 24 July 2020; published online July 29, 2020. a S.P. and E.S. are equally contributing last authors. Correspondence: Eike Steinmann, PhD, Department of Molecular and Medical Virology, RuhrUniversity Bochum, Universitaetsstr 150, 44801 Bochum, Germany (eike.steinmann@rub.de). The Journal of Infectious Diseases®  2020;222:1289–92 © The Author(s) 2020. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com. DOI: 10.1093/infdis/jiaa471 METHODS Virus Strains and Propagation To isolate SARS-CoV-2 at the University Ulm Medical Center (Ulm, Germany), 50 000 Vero E6 cells were seeded in 24-well plates in 500 µL medium incubated overnight at 37°C. The next day, medium was replaced by 400 µL of 2.5 µg/mL amphotericin B–containing medium. Then, 100 µL of throat swabs that tested positive for SARS-CoV-2 by reverse-transcription quantitative polymerase chain reaction was titrated 5-fold on the cells and incubated for 3–5 days. Upon visible cytopathic effect, supernatant was taken and virus expanded by inoculation of Vero E6 cells in 75 cm2 flasks and propagated as described above. Thereby, the viral isolates BetaCoV/Germany/Ulm/01/2020 (strain 2) and BetaCoV/Germany/Ulm/02/2020 (strain 3) were obtained. In Essen, Germany, SARS-CoV-2 was isolated from a nasopharyngeal swab of a patient suffering from coronavirus disease 2019 (COVID-19) and named UKEssen strain (strain 1). The swab was taken using a Virocult vial (Sigma, Germany). The..