Sir, I was disappointed to read the statement in an otherwise excellent document from the FGDP and College of General Dentistry that pre-treatment antiviral mouthwash was not recommended because of 'a lack of evidence of virucidal activity for use of pre-operative mouthwash'. I wonder if a flurry of recent papers, possibly overlooked, might lead to a questioning of that statement. What is now known is that SARS-CoV-2 replicates in the oral cavity and that extremely high numbers (>10 million) of infectious viral particles per ml saliva can be found at an early stage in SARS-CoV-2 infection.1 The virus in saliva is not contamination from elsewhere, but reflects active replication probably in ACE2 positive epithelial cells in minor salivary glands.2 Similar high levels are found in the nose.3

This is clearly an infection risk to any clinician working around the mouth or nose. Any virucidal agent applied to those sites may substantially reduce the risk of cross infection.4

Several commonly used antiseptic mouthwashes with anti-bacterial activity also have anti-viral activity against coronaviruses demonstrated in vitro.5 Two (povidone iodine and ethanol) have been shown to have substantial activity against SARS-CoV-2 and one (PVP-I) SARS-CoV in the presence of organic matter designed to replicate in vivo conditions.6 What is not known is how effective any anti-viral mouthwash actually is in vivo, nor how long the antiviral effect lasts. This has been estimated as greater than 20 minutes.4 Thus, does one recommend withholding a potentially effective agent (thus potentially exposing substantial numbers of dental HCWs to extra risk), or does one recommend that a simple, cheap, safe and potentially effective agent is used to help safeguard the profession while the extra information is sought?

PVP-I has been used in dentistry for over 60 years and its safety profile well established.4 Over 24 dental HCWs have now died with SARS-CoV-2. Anything which helps to keep the profession as safe as possible is surely to be supported.