Can mouthwash inactivate coronavirus? Here’s the research…

Mouthwash has come a long way from simply freshening your breath. Nowadays when you go to your local drugstore you can find any number of therapeutic oral rinses that provide all kinds of benefits.

For instance, if you’re particularly prone to plaque buildup on your teeth, adding a therapeutic oral rinse to your dental care routine can help reduce the amount of plaque and bacteria in your mouth. This helps prevent gum diseases like gingivitis, which can lead to tooth loss and other health problems. Many oral rinses also contain fluoride, which helps prevent cavities and mineral loss in your teeth.

Recently, researchers discovered another potential benefit of oral rinses — one that is very timely…

The impact of oral rinses on coronaviruses

According to a recent study by Penn State College of Medicine, certain oral antiseptics and mouthwashes could inactivate human coronaviruses. Based on these results, some of these products might be useful for reducing the amount of virus in the mouth after infection and may help to reduce the spread of SARS-CoV-2, the coronavirus that causes COVID-19.

A group of physicians and scientists tested several oral and nasopharyngeal rinses for their ability to inactivate human coronaviruses, which are similar in structure to SARS-CoV-2. Some of the products they examined include a 1 percent solution of baby shampoo, a neti pot, peroxide cleansers for sore mouth and mouthwashes.

Several of the nasal and oral rinses showed a strong ability to neutralize human coronavirus, suggesting that these products could potentially reduce the amount of virus spread by people who have tested positive for COVID-19.

Since nasal and oral cavities are major points of entry and transmission for coronaviruses, the researchers used a test that replicated the interaction between the virus in the nasal and oral cavities with the rinses and mouthwashes. They used a strain of human coronavirus that was readily available and genetically similar to SARS-CoV-2.

The team allowed the baby shampoo solution, various peroxide antiseptic rinses and various brands of mouthwash to interact with the virus for 30 seconds, one minute and two minutes, then diluted the solutions to prevent further virus inactivation.

To measure how much virus was inactivated, the researchers placed the diluted solutions in contact with cultured human cells and counted how many cells remained alive after a few days of exposure to the viral solution. Then, they used that number to calculate the amount of human coronavirus inactivated because of exposure to the mouthwash or oral rinse.

Impressive results

The 1 percent baby shampoo solution, which head and neck doctors often use to rinse the sinuses, inactivated greater than 99.9 percent of human coronavirus after a two-minute contact time. By contrast, the neti pot, often used with a saltwater solution, did not inactivate any virus.

Several of the mouthwash and gargle products also were effective, with many inactivating greater than 99.9 percent of the virus after only 30 seconds of contact time and some inactivating 99.99 percent of the virus after 30 seconds.

For example, several of the antiseptic mouthwashes such as Listerine, Equate and CVS showed viral inactivation of greater than or equal to 99.99 percent after only 30 seconds of exposure.

This study reinforces the findings of a study published in July that noted the ability of certain types of oral rinses to inactivate SARS-CoV-2. The Penn State study evaluated the solutions at longer contact times and studied products that were not tested in the July study.

Lead researcher Craig Meyers says the next step is to design and conduct clinical trials to evaluate whether products like oral rinses can effectively reduce viral load in COVID-19 patients. Future studies could examine what specific ingredients in the tested solutions inactivate the virus, as well as investigate other products that inactivate human coronavirus.

“People who test positive for COVID-19 and return home to quarantine may possibly transmit the virus to those they live with,” says Meyers, a researcher at Penn State Cancer Institute. “Certain professions including dentists and other health care workers are at a constant risk of exposure. Clinical trials are needed to determine if these products can reduce the amount of virus COVID-positive patients or those with high-risk occupations may spread while talking, coughing or sneezing. Even if the use of these solutions could reduce transmission by 50 percent, it would have a major impact.”

However, mouthwash should “not to replace wearing masks and social distancing,” added Meyers.

Best practices for mouth rinsing

This is great news. Since masks are not 100 percent effective at halting the spread of the coronavirus, used together, mouthwash and masking-up could be a stronger strategy. Especially since we know the virus spreads easily from droplets expelled when an infected person speaks or coughs. And since previous research has shown the virus replicates significantly in the throat.

To effectively use an oral rinse, make sure you thoroughly brush and floss your teeth beforehand. If you use fluoride-based toothpaste, dentists recommend waiting at least 30 minutes before using the mouth rinse.

Use only as much mouthwash as instructed on the bottle — many come with a measuring cup you can use to get precisely the right amount. Empty the cup into your mouth and swish it around or gargle for at least 30 seconds before spitting it out. Don’t swallow it — it’s not meant to be ingested.

If you decide to use a therapeutic oral rinse, be aware that there are some drawbacks. Alcohol-based mouthwashes can cause dry mouth, and oral rinses can get rid of the good bacteria in your mouth along with the bad. There have been fears that the use of alcohol-based mouth rinses can cause oral cancer, but so far, no definite connection has been found.

Sources:

3 Mouthwash Benefits & Risks (What to Look For) — The Silverstrom Group

Mouthwashes, oral rinses may inactivate human coronaviruses — Penn State News

Lowering the transmission and spread of human coronavirus — Journal of Medical Virology

Virucidal Efficacy of Different Oral Rinses Against Severe Acute Respiratory Syndrome Coronavirus 2 — The Journal of Infectious Diseases

Everything You Need to Know About Using Mouthwash — Healthline