In vitro virucidal activity of povidone iodine gargle and mouthwash against SARS-CoV-2: implications for dental practice

Abstract

Introduction Virus particles in respiratory droplets and aerosols generated during medical/dental procedures are a potential source of SARS-CoV-2 cross infection. In the dental setting, oral decontamination could be an important adjunct to personal protective equipment and is recommended by a number of national COVID-19 guidance documents for dental settings.

Aim To assess the in vitrovirucidal activity of an oral povidone iodine (PVP-I) product against SARS-CoV-2.

Material and methods BETADINE gargle and mouthwash (1% PVP-I) was tested against SARS-CoV-2 virus under both clean and dirty conditions using a suspension assay based on EN14476 methodology. Virucidal activity of the product, undiluted and at 1:2 dilution, was tested at contact times of 15, 30 and 60 seconds. Viral titres were calculated using the Spearman-Kärber method and reported as median tissue culture infectious dose (TCID ₅₀/ml).

Results The undiluted product achieved >5 log10 reduction in viral titres compared to the control at 15, 30 and 60 seconds under both clean and dirty conditions. At a twofold dilution (0.5% PVP-I), the test product demonstrated >4 log10 kill at 15 seconds and >5 log10 kill at 30 and 60 seconds in both clean and dirty conditions.

Conclusion PVP-I gargle and mouthwash product, undiluted and at 1:2 dilution, demonstrated potent and rapid virucidal activity (≥4 log10 reduction of viral titre) in 15 seconds against SARS-CoV-2 in vitro. The PVP-I gargle and mouthwash product is widely available and could be readily integrated into infection control measures during dental treatment including pre-procedural oral decontamination.

Key points

• Close contact and potential for aerosol generation increase risk of SARS-CoV-2 exposure during medical and dental procedures.

• Pre-procedural mouth rinses are recommended as an additional measure to reduce cross-infection risk in dental settings.

• PVP-I (1%) gargle and mouthwash showed 99.99% kill rate of SARS-CoV-2 in vitro within 15 seconds of contact in clean and dirty conditions.

• The use of PVP-I-containing pre-procedural mouth rinse to reduce oral viral load could be recommended in addition to other protective measures.