Abstract: PLOS ONE RESEARCH ARTICLE Efficacy of “Essential Iodine Drops” against Severe Acute Respiratory SyndromeCoronavirus 2 (SARS-CoV-2) Zoltán Köntös* IOI Investment Zrt., Fehérvári út, Budapest, Hungary * zkontos@ioi-investment.com a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 OPEN ACCESS Citation: Köntös Z (2021) Efficacy of “Essential Iodine Drops” against Severe Acute Respiratory Syndrome-Coronavirus 2 (SARS-CoV-2). PLoS ONE 16(7): e0254341. https://doi.org/10.1371/ journal.pone.0254341 Editor: Raffaele Serra, University Magna Graecia of Catanzaro, ITALY Received: November 3, 2020 Accepted: June 25, 2021 Published: July 9, 2021 Copyright: © 2021 Köntös Zoltán. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All relevant data are within the manuscript. Funding: This study was funded by IOI Investment Zrt., who also provided support for this study in the form of salary for ZK. The specific roles of these authors are articulated in the ‘author contributions’ section. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing interests: The authors have read the journal’s policy and the authors of this manuscript have the following competing interests: ZK is a paid Abstract Background Aerosolization of respiratory droplets is considered the main route of coronavirus disease 2019 (COVID-19). Therefore, reducing the viral load of Severe Acute Respiratory Syndrome-Coronavirus 2 (SARS-CoV-2) shed via respiratory droplets is potentially an ideal strategy to prevent the spread of the pandemic. The in vitro virucidal activity of intranasal Povidone-Iodine (PVP-I) has been demonstrated recently to reduce SARS-CoV-2 viral titres. This study evaluated the virucidal activity of the aqueous solution of Iodine-V (a clathrate complex formed by elemental iodine and fulvic acid) as in Essential Iodine Drops (EID) with 200 μg elemental iodine/ml content against SARS-CoV-2 to ascertain whether it is a better alternative to PVP-I. Methods SARS-CoV-2 (USAWA1/2020 strain) virus stock was prepared by infecting Vero 76 cells (ATCC CRL-1587) until cytopathic effect (CPE). The virucidal activity of EID against SARSCoV-2 was tested in three dilutions (1:1; 2:1 and 3:1) in triplicates by incubating at room temperature (22 ± 2˚C) for either 60 or 90 seconds. The surviving viruses from each sample were quantified by a standard end-point dilution assay. Results EID (200 μg iodine/ml) after exposure for 60 and 90 seconds was compared to controls. In both cases, the viral titre was reduced by 99% (LRV 2.0). The 1:1 dilution of EID with virus reduced SARS-CoV-2 virus from 31,623 cell culture infectious dose 50% (CCID50) to 316 CCID50 within 90 seconds. Conclusion Substantial reductions in LRV by Iodine-V in EID confirmed the activity of EID against SARS-CoV-2 in vitro, demonstrating that Iodine-V in EID is effective at inactivating the virus in vitro and therefore suggesting its potential application intranasally to reduce SARS-CoV-2 transmission from known or suspected COVID-19 patients. PLOS ONE | https://doi.org/10.1371/journal.pone.0254341 July 9, 2021 1/7 PLOS ONE employee of IOI Investment Zrt, the manufacturing company of Iodine-V and EID...