Listerine: Our Mouthwash ‘Is Not Intended To Prevent Or Treat Covid

Listerine created a web page just to answer questions about their mouthwash and Covid-19 ... [+] coronavirus. (AP Photo/Gene J. Puskar)

Listen to Listerine. Not the mouthwash itself, since mouthwash shouldn't be talking to you, but the makers of the mouthwash.

They’ve got a response to the reaction generated by a new study out of Cardiff University. This study suggested that mouthwashes consisting of 0.07% cetylpyridinium chloride (CPC) may be able to kill the Covid-19 coronavirus. Despite having major limitations, this study prompted reactions on social media such as:

And:

Then there was this:

It's not completely clear why you would need staples to last three weeks.

Regardless, all of this came after a"Brief Report" was uploaded to BioRxiv by a team from the School of Medicine and the School of Dentistry at Cardiff University. Uploaded to a website like bioRxiv does not mean published in a reputable peer-reviewed scientific journal. No it means that the Brief Report authors (Evelina Statkute, Anzelika Rubina, Valerie B O’Donnell, David W. Thomas, and Richard J. Stanton) somehow had access to the Internet, that someone's cat didn't smash up their routers, and that they were able to complete the forms that bioRxiv requires to upload a paper. The bioRxiv procedure does prevent people from uploading pictures of bare chested men holding fish but it does not evaluate the scientific quality and merit of the study. So take anything that this Brief Report says with several mouthwash bottles full of salt.

The "Brief Report" described an experiment performed by the Cardiff University team. In a laboratory, they created a mixture of cells, mucin, and yeast that was supposed to "mimic" the conditions in your mouth. Keep in mind that your mouth is not actually just a collection of cells, mucin, and yeast. At least, it shouldn't be. If it is, see a doctor as soon as possible.

For the experiment, the team introduced the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to this mixture and determined how exposing the virus to different rinses for 30 seconds affected the virus's ability to infect the cells. According to the report, the two rinses that contained cetylpyridinium chloride and the rinse that had ethanol/ethyl lauroyl arginate reduced the amount of live virus by over four logs. The rinses with ethanol/essential oils and povidone-iodine (PVP-I) reduced the amount of live virus by two to three logs, while chlorhexidine or ethanol alone was not able to inactivate the virus.

In this case, logs have nothing to do with large trees. A one log reduction would be a reduction of live virus quantities by 10 times or a 90% reduction. A two log reduction would be by 100 times or 99%. A three log would be 1,000 or 99.9%. And a four log would be 10,000 or by 99.99%. All of this sounds interesting but again this study has not been peer reviewed and was performed in a lab without using actual human beings.

As I have written before for Forbes, demonstrating that mouthwash can kill the Covid-19 coronavirus in the laboratory is very different from showing that it can actually prevent Covid-19 coronavirus infections in people in any way. This would be like saying simply using mouthwash will be enough for you to have a successful date. For example, showing up without a shirt and carrying a large fish could end up impacting your date.

Indeed, claims about mouthwash killing Covid-19 coronavirus have gotten so prevalent that Listerine has created a special web page to address such claims. And the web page clearly says, "Listerine mouthwash has not been tested against any strains of coronavirus."

Not tested against any strain means not tested against the Covid-19 coronavirus as well. The Listerine website emphasizes that, "Listerine Antiseptic is a daily mouthwash which has been proven to kill 99.9% of germs that cause bad breath, plaque and gingivitis." The Covid-19 coronavirus is not one of those germs that simply cause bad breath, plaque, and gingivitis. This isn't a pandemic of halitosis. No one should be saying, "oh your breath is kind of stinky. It may be the Covid-19 coronavirus. Maybe you should rinse your mouth or just not open it during the date." The Covid-19 coronavirus is a whole lot more serious. The Listerine website states that Listerine mouthwash "is not intended to prevent or treat Covid-19."

An ongoing concern is that people are trying to find something to replace what you actually should be doing to prevent the spread of the Covid-19 coronavirus. As the Listerine website explains, "Consumers should follow the preventive measures issued by the World Health Organization including washing hands frequently, maintaining social distance and avoid touching your eyes, nose and mouth." Add to this list face mask use, which incidentally can help combat bad breath as well as the Covid-19 coronavirus.

And remember those unsupported claims that emerged early on in the pandemic that gargling with salt water, mouthwash or other substances can somehow rid your throat of the Covid-19 coronavirus? Well, the Listerine website says that you shouldn't even gargle with their mouthwash for any reason. "Listerine mouthwash is not intended to be gargled in the throat, but rather, swished in the mouth." That's why it's called mouthwash and not throatwash or throatgargle. And it's certainly not called inhale-into-your-respiratory-system-wash. Washing your mouth won't remove the virus from your respiratory system, which is where the Covid-19 coronavirus tends to initially infect. Just because a virus gives you a sore throat doesn't mean that the virus is mainly in your throat

Oh, and if you are thinking pouring mouthwash on your hands to wash them or covering you furniture with Listerine, don't. There are things called soap, hand sanitizer, and disinfectant to do such things. As the Listerine website warns, "The Centers for Disease Control and Prevention (CDC) recommends the use of a hand sanitizer that contains at least 60% alcohol in order to protect yourself. Only some Listerine mouthwash formulations contain alcohol, and if present is only around 20% alcohol. Listerine mouthwash is not intended to be used, nor would it be beneficial as a hand sanitizer or surface disinfectant." Covering your furniture with mouthwash may make your apartment smell like a gigantic mouth that happens to be cool and minty, but it may not be enough to kill germs like the Covid-19 coronavirus. Comparing mouthwash to hand soap and disinfectant would be like comparing a hat to underwear and socks. Wearing either underwear or a sock on your head may not have the same intended effect. And trying to wear socks where your underwear normally goes? Well, that may not be a pretty picture.

Regardless of whether the study from Cardiff University ends up being published in a peer-reviewed scientific journal, it alone does not offer evidence that mouthwash will help prevent the spread of the Covid-19 coronavirus among humans in any way. Your body may be a wonderland, but it is also very complex. If your body were as simple as a table or a bunch of cells mixed with some goop in a test tube, you could possibly just cover it with disinfectant. But it isn't and you shouldn't ingest or inject disinfectant, not that anyone would ever suggest doing so.

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