Sir, dentists and their assistants as front-line healthcare workers (HCW) in close contact with the upper aerodigestive tract are at especial risk of transmission of the coronavirus from patients. In early infection, viral titres of greater than 107/mL in saliva and nasal mucous can be found and thus any work within the oral cavity carries an increased risk.1 Even a few microlitres of saliva contamination of surfaces or instruments may carry many thousands of infectious viral particles. A significant proportion of COVID-19 sufferers are asymptomatic, but shedding these viral particles.
We have been examining the potential role of povidone iodine (PVP-I) in the reduction of the risk of cross infection and protection of dentists and other HCW from COVID-19 and have drafted a paper summarising the evidence.2
PVP-I has a better anti-viral activity than other antiseptics such as chlorhexidine,3 and has already been proven to be an effective virucide in vitro against similar coronaviruses (SARS-CoV and MERS-CoV)4 although it has not been tested directly with COVID-19. PVP-I has been shown to be a safe therapy when used as a mouthwash or taken nasally. We propose that a protocolised nasal spray and oropharyngeal wash of PVP-I should be used in the current COVID-19 pandemic to limit the spread of SARS-CoV-2 from patients to healthcare workers and potentially vice versa. We propose that no dental patient should be examined before disinfection by PVP-I. The reduction in coronavirus titres is over 99.99% in vitro3 and we estimate the reduction to last for at least 20 minutes in vivo. The exact length of time is being researched, but should be sufficient for examination and short procedures.
Elsewhere we describe similar protocols for treating known COVID-19+ patients and the HCW looking after them.2 The total iodine exposure proposed is well within previously recorded safe limits in those without contraindications to its use (history of allergy to PVP, thyroid disease etc). The intervention is inexpensive, easy and easily deployed at scale. The methodology proposed is as follows:
Step 1 - A 0·5% PVP-I solution (standard aqueous PVP-I antiseptic solution diluted 1:20 with water) is administered in a dose of 0·3 ml into each nostril, preferably using an atomising device (two sprays for average device) or if not from a syringe.
Step 2 - 9 ml of the 0.5% solution is then introduced into the oral cavity and used as a mouthwash. Distribute throughout the oral cavity for 30 seconds and then gently gargle at the back of the throat for another 30 seconds before spitting out.
We propose the use of PVP-I applied as per this method for all patients requiring dental treatment during the current COVID-19 pandemic, just prior to treatment. To enhance protection, the operating dental surgeon and assistant should both consider self-administering to the same protocol every 2-3 hours while treating patients during the pandemic, up to four times a day, as an adjunct to currently recommended PPE. The application of PVP-I mouthwash and nasal spray in this way should reduce the cross-infection risk and therefore help to protect dentists. The American Dental Association have very recently published interim guidelines for minimising the risk of COVID-19 transmission which includes the use of a pre-operative 0.2% povidone mouthwash.5
A more comprehensive summary of the available evidence, safety data and exclusion criteria are available and we would recommend that this is read before using this protocol.2
To K K-W, Tsang OT-Y, Chik-Yan Yip C et al. Consistent detection of 2019 novel coronavirus in saliva. Clin Infect Dis 2020; 361: 1319-1326.
Kirk-Bailey J, Combes J, Sunkaraneni S, Challacombe S. The use of Povidone Iodine nasal spray and mouthwash during the current COVID-19 pandemic for the reduction of cross infection and protection of healthcare workers. (submitted) Last revised 16 April 2020. Available at: https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3563092 (accessed 22 April 2020).
Eggers M, Koburger-Janssen T, Eickmann M, Zorn J. In vitro bactericidal and virucidal efficacy of Povidone-Iodine gargle/mouthwash against respiratory and oral tract pathogens. Infect Dis Ther 2018; 7: 249-259.
Kariwa H, Fujii N, Takashima I. Inactivation of SARS coronavirus by means of povidone-iodine, physical conditions and chemical reagents. Dermatology 2006; 212 Suppl: 119-123.
American Dental Association (ADA) Interim Guidance for Minimizing Risk of COVID-19 Transmission 2020. Available at: https://bit.ly/3bskHOx (accessed 22 April 2020).
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Challacombe, S., Kirk-Bayley, J., Sunkaraneni, V. et al. Povidone iodine. Br Dent J 228, 656–657 (2020). https://doi.org/10.1038/s41415-020-1589-4
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