Mouthwash can kill COVID-19 in 30 seconds, preliminary lab study finds

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TORONTO — A new study has found that over-the-counter mouthwash can kill coronavirus within 30 seconds of exposure in a lab setting.

The study, conducted by researchers at Cardiff University, found that mouthwash containing at least 0.07 percent cetylpyridinium chloride (CPC) showed "promising signs" of reducing transmission of the virus in human saliva.

The report, which was released on Friday, has yet to be peer-reviewed but supports another study published in early November that found CPC-based mouthwashes are effective in reducing COVID-19’s viral load.

In the preliminary report, researchers tested how effective a handful of mouthwash brands, including Dentyl and Listerine, containing ethanol/essential oils, cetylpyridinium chloride (CPC) and povidone-iodine (PVP-I) were at eradicating the virus.

They found that three of the mouthwashes they tried eradicated the virus completely in a lab setting. Out of these three products, two contained at least 0.07 per cent CPC and the third contained 23 per cent ethanol with ethyl lauroyl arginate (LAE).

Researchers suggest that ethanol alone at had no effect on the virus, and the "inclusion of essential oils [such as in Listerine Cool Mint] or [the compound] LAE [found in Listerine Advanced] appears to be required for optimal efficacy," according to the report.

While the report suggests that the use of mouthwash may help kill the virus in saliva, this does not mean that mouthwash could be used as a treatment for the novel coronavirus or act as a cure. Experts say the initial results are encouraging, but more research is needed.

The researchers stressed that the findings are preliminary, and people should still follow the preventive measures outlined by public health experts, including physical distancing and hand washing.

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 and evaluate how long the effect lasts.

Researchers noted the clinical trial will not produce evidence of how to prevent transmission between patients using mouthwash. The results are expected to be published in early 2021.

According to the World Health Organization, COVID-19 spreads from an infected person’s mouth or nose in small liquid particles referred to as "respiratory droplets" when the person coughs, sneezes, speaks, or breathes heavily.

With that in mind, theoretically, it should make sense then that oral care may help eliminate virus particles in one’s mouth. However, experts warn that there is little research to prove such claims.

The Canadian Dental Association recommends that Canadians keep up with their oral health care amid the ongoing pandemic, including regular use of things like toothpaste that help control the bacteria in the mouth to prevent cavities and periodontal disease.