Support for earlier studies on efficacy of OTC mouthwashes against SARS-CoV2

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An over-the-counter mouthwash can kill SARS-CoV2 within 30 seconds of being exposed to it, found a Cardiff University in vitro study

The preliminary result comes ahead of a clinical trial into whether using over-the-counter mouthwash could to reduce the levels of Covid-19 in a patient’s saliva. Two earlier preliminary studies using very small numbers of patients with COVID19 have suggested that cetypyridinium chloride-based mouthwashes may reduce SARS-CoV2 loads in vivo.

The Cardiff University report said that mouthwashes containing at least 0.07 per cent cetypyridinium chloride (CPC) showed “promising signs” of combatting the virus. The report is yet to be peer reviewed.

The latest test was carried out by scientists at the university’s laboratory and mimicked the conditions of a person’s naso/oropharynx passage using various mouthwash brands, including Dentyl and Listerine.

A clinical trial will next examine how effective mouthwash is in reducing the viral load in the saliva of Covid-19 patients at the University Hospital of Wales in Cardiff, with its results due to be published in the first part of 2021.


The ability of widely-available mouthwashes to inactivate SARS-CoV-2 in vitro was tested using a protocol capable of detecting a 5-log10 reduction in infectivity, under conditions mimicking the naso/oropharynx. During a 30 second exposure, two rinses containing cetylpyridinium chloride and a third with ethanol/ethyl lauroyl arginate eliminated live virus to EN14476 standards (>4-log10 reduction), while others with ethanol/essential oils and povidone-iodine (PVP-I) eliminated virus by 2-3-log10. Chlorhexidine or ethanol alone had little or no ability to inactivate virus in this assay. Studies are warranted to determine whether these formulations can inactivate virus in the human oropharynx in vivo, and whether this might impact transmission.


Full BioRxiv report (Open Access)(Not peer reviewed)


See also:


MedicalBrief Archives: Some OTC mouthwashes neutralise human coronaviruses

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