Comparison of In Vitro Inactivation of SARS CoV-2 with Hydrogen Peroxide and Povidone-Iodine Oral Antiseptic Rinses

To evaluate the in vitro inactivation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with hydrogen peroxide (H₂ O₂ ) and povidone-iodine (PVP-I) oral antiseptic rinses at clinically recommended concentrations and contact times.

SARS-CoV-2, USA-WA1/2020 strain virus stock was prepared prior to testing by growing in Vero 76 cells. The culture media for prepared virus stock was minimum essential medium (MEM) with 2% fetal bovine serum (FBS) and 50 µg/mL gentamicin. Test compounds consisting of PVP-I oral rinse solutions and H₂ O₂ aqueous solutions were mixed directly with the virus solution so that the final concentration was 50% of the test compound and 50% of the virus solution. Thus PVP-I was tested at concentrations of 0.5%, 1.25%, and 1.5%, and H₂ O₂ was tested at 3% and 1.5% concentrations to represent clinically recommended concentrations. Ethanol and water were evaluated in parallel as standard positive and negative controls. All samples were tested at contact periods of 15 seconds and 30 seconds. Surviving virus from each sample was then quantified by standard end-point dilution assay and the log reduction value of each compound compared to the negative control was calculated.

After the 15-second and 30-second contact times, PVP-I oral antiseptic rinse at all 3 concentrations of 0.5%, 1.25%, and 1.5% completely inactivated SARS-CoV-2. The H₂ O₂ solutions at concentrations of 1.5% and 3.0% showed minimal viricidal activity after 15 seconds and 30 seconds of contact time.

SARS-CoV-2 virus was completely inactivated by PVP-I oral antiseptic rinse in vitro, at the lowest concentration of 0.5 % and at the lowest contact time of 15 seconds. Hydrogen peroxide at the recommended oral rinse concentrations of 1.5% and 3.0% was minimally effective as a viricidal agent after contact times as long as 30 seconds. Therefore, preprocedural rinsing with diluted PVP-I in the range of 0.5% to 1.5% may be preferred over hydrogen peroxide during the COVID-19 pandemic.