A study investigated the optimal contact time and concentration for the viricidal activity of oral preparation of Povidone-Iodine (PVP-I) against SARS-CoV-2 (coronavirus) to mitigate the risk and transmission of the virus in the dental practice. The investigators tested the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) USA-WA1/2020 strain, virus stock against oral antiseptic solutions comprising aqueous Povidone-Iodine (PVP-I) as the sole active ingredient. The test solutions of PVP-I was diluted in concentrations of 0.5%, 1%, and 1.5%. 

Test media minus virus was added to 2 tubes of the compounds to serve as toxicity and neutralization controls. Parallelly, Ethanol (70%) was tested as a positive control, and water as a negative control. Incubation of test solutions and viruses were carried out at room temperature (22 ± 2 °C) for periods of 15 and 30 seconds. 1/10 dilution in minimum essential medium (MEM) 2% fetal bovine serum (FBS), 50 µg/mL gentamicin was utilized to Neutralize the solution. Surviving virus from each sample was finally quantified and compared with the negative (water) control.

It was observed that all the tested concentrations of PVP-I oral antiseptics completely inactivated SARS-CoV-2 within 15 seconds of contact.

The 70% ethanol control group did not completely inactivate SARS-CoV-2 after 15 seconds of contact and it was able to inactivate the virus at 30 seconds of contact.

The study concluded that PVP-I oral antiseptic preparations have the capability to rapidly inactivate the SARS-CoV-2 virus in vitro. The viricidal activity of PVP-I can be achieved at the lowest concentration of 0.5 % PVP-I and at the lowest contact time of 15 seconds. 

PVP-I therefore can be used for preprocedural oral rinsing as an adjunct to personal protective equipment in dental and surgical specialities during the COVID-19 pandemic.

Bidra AS, et al. e . J Prosthodont. 2020 Jul;29(6):529-533.