Study finds certain mouthwashes have a very timely health benefit

What do you think your reaction would have been if a friend pulled you aside one day last year and said: “A new virus will appear in 2020 that’s going to devastate the global economy, kill hundreds of thousands of people, spread super quickly and efficiently from person to person, and the summer heat won’t slow it down at all.”

Hindsight is 20/20, but at the time it’s pretty safe to say that everyone would have laughed at their friend and told them to stop living in a fantasy world. Indeed, the coronavirus and its deadly characteristics took absolutely everyone, including the world’s leading doctors and scientists, by surprise. Right from the start, everything about this virus has felt unusual, which is why the latest findings out of Ruhr-Universität Bochum in Germany are so surprising.

Researchers there have discovered that certain commercially available mouthwashes (including cool mint Listerine) are capable of “inactivating” SARS-CoV-2 within infected patients’ mouths and throats.

For a virus that has proven invulnerable or resistant to so much, it’s fascinating that some mouthwashes appear to do the trick against COVID-19.

Before you go out and raid the closest dental aisle, the study’s authors aren’t saying mouthwash is a viable treatment option for COVID-19 patients. Nor will using mouthwash protect anyone from personally contracting the coronavirus. But, certain mouthwashes did show the ability to neutralize SARS-CoV-2 within infected patients’ mouths and throats.

This suggests that mouthwashes can be used to lower the “viral load” infected parties are carrying while harboring the virus, and possibly reduce the chances of said infected person spreading SARS-CoV-2 to someone else. 

For example, let’s say Larry is an asymptomatic coronavirus carrier. As far as Larry knows, he’s completely healthy, so he decides to have his teeth cleaned. Before leaving home, Larry uses some mouthwash. That decision to use some mouthwash may have saved his dentist from catching coronavirus. 

“Gargling with a mouthwash cannot inhibit the production of viruses in the cells,” explains study leader Toni Meister in a release, “but could reduce the viral load in the short term where the greatest potential for infection comes from, namely in the oral cavity and throat – and this could be useful in certain situations, such as at the dentist or during the medical care of Covid-19 patients.”

A total of eight mouthwash brands available in German stores and pharmacies were tested for this research. To start, each mouthwash was mixed with coronavirus particles and an “interfering substance” (as a stand-in for saliva). Then, each concoction was shaken for 30 seconds to recreate the act of gargling. 

After all that, researchers used Vero e6 cell cultures to determine how much of the coronavirus remained in each mixture. Those cells are particularly receptive to the coronavirus, making them an ideal choice for this phase of the experiment.

To varying degrees, all eight included types of mouthwash displayed the ability to subdue or inactivate the coronavirus, but three brands of mouthwash stood above the rest. Those three were Dequonal, Iso-Betadine mouthwash 1.0%, and cool mint Listerine. That trio was able to completely erase any trace of SARS-CoV-2 after 30 seconds of exposure. 

These findings, while no doubt promising, should be confirmed in real-world scenarios outside of a lab, the research team says. Also, as of now, it’s unclear for just how long a good gargle with mouthwash inactivates the virus.

The team at Bochum is already making plans for a clinical study on this topic.

The full study can be found here, published in the Journal of Infectious Diseases.