Written By Kevin Kerfoot / Reviewed By Ray Spotts
Certain oral antiseptics and mouthwashes may have the ability to inactivate human coronaviruses, according to a Penn State College of Medicine research study published in the Journal of Medical Virology. Some of these products might be useful for reducing the viral load - 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.
The products evaluated include a one percent solution of baby shampoo, a neti pot, peroxide sore-mouth cleansers, and mouthwashes. Several of the nasal and oral rinses had a strong ability to neutralize human coronavirus, which suggests that these products may have the potential to reduce the amount of virus spread by people who are COVID-19-positive.
The mouthwash results are promising and add to the findings of a study showing that certain types of oral rinses could inactivate SARS-CoV-2 in similar experimental conditions. In addition to evaluating the solutions at longer contact times, they studied over-the-counter products and nasal rinses that were not evaluated in the other study.
The next step to expand upon these results is to design and conduct clinical trials that evaluate whether products like mouthwashes can effectively reduce viral load in COVID-19-positive patients.
Gargle and mouthwash products and coronavirus
The one percent baby shampoo solution - often used by head and neck doctors to rinse the sinuses - inactivated greater than 99.9 percent of human coronavirus after a two-minute contact time.
Several of the mouthwash and gargle products also were effective at inactivating the infectious virus. Many inactivated greater than 99.9 percent of virus after only 30 seconds of contact time and some inactivated 99.99 percent of the virus after 30 seconds.
Nasal and oral cavities are major points of entry and transmission for human coronaviruses. The researchers used a test to replicate the interaction of the virus in the nasal and oral cavities with the rinses and mouthwashes.
They treated solutions containing a strain of human coronavirus, which served as a readily available and genetically similar alternative for SARS-CoV-2, with the baby shampoo solutions, various peroxide antiseptic rinses and various brands of mouthwash. They allowed the solutions to interact with the virus for 30 seconds, one minute and two minutes, before diluting the solutions to prevent further virus inactivation.
The outer envelopes of the human coronavirus tested and SARS-CoV-2 are genetically similar so the research team hypothesizes that a similar amount of SARS-CoV-2 may be inactivated upon exposure to the solution.
The researchers placed the diluted solutions in contact with cultured human cells to measure how much virus was inactivated They counted how many cells remained alive after a few days of exposure to the viral solution and used that number to calculate the amount of human coronavirus that was inactivated as a result of exposure to the mouthwash or oral rinse that was tested.
Future studies may include a continued investigation of products that inactive human coronaviruses and what specific ingredients in the solutions tested inactivate the virus.
"While we wait for a vaccine to be developed, methods to reduce transmission are needed," says Craig Meyers, distinguished professor of microbiology, immunology, obstetrics and gynecology, and researcher at Penn State Cancer Institute. "The products we tested are readily available and often already part of people's daily routines. While we wait for a vaccine to be developed, methods to reduce transmission are needed.
“People who test positive for COVID-19 and return home to quarantine may possibly transmit the virus to those they live with. 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."
Mouthwashes could reduce the risk of coronavirus transmission
In another recent study – published in the Journal of Infectious Diseases - researchers found that Sars-Cov-2 viruses can be inactivated using certain commercially available mouthwashes. This was demonstrated in cell culture experiments by virologists from Ruhr-Universität Bochum together with colleagues from Jena, Ulm, Duisburg-Essen, Nuremberg and Bremen.
The use of mouthwashes that are effective against Sars-Cov-2 could help reduce the viral load and possibly the risk of coronavirus transmission over the short term. High viral loads can be detected in the oral cavity and throat of some Covid-19 patients. This could be useful prior to dental treatments. However, mouth rinses are not suitable for treating Covid-19 infections or protecting yourself against catching the virus.
Testing mouthwashes for coronavirus results
The researchers tested eight mouthwashes with different ingredients that are available in pharmacies or drugstores in Germany. They mixed each mouthwash with virus particles and an interfering substance, which was intended to recreate the effect of saliva in the mouth.
The mixture was then shaken for 30 seconds to simulate the effect of gargling. They then used Vero E6 cells, which are particularly receptive to Sars-Cov-2, to determine the virus titer. They also treated the virus suspensions with cell culture medium instead of the mouthwash before adding them to the cell culture.
All of the tested preparations reduced the initial virus titer. Three mouthwashes reduced it to such an extent that no virus could be detected after an exposure time of 30 seconds. Whether this effect is confirmed in clinical practice and how long it lasts must be investigated in further studies. The authors stress that mouthwashes are not suitable for treating Covid-19.
Currently, The Bochum researchers are in contact with the American researchers and examining the possibilities of a clinical study on the efficacy of mouthwashes on Sars-Cov-2 viruses, during which the scientists want to test whether the effect can also be detected in patients and how long it lasts. Similar studies are already underway in San Francisco.
"Gargling with a mouthwash cannot inhibit the production of viruses in the cells, 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,” added professor Toni Meister. “This could be useful in certain situations, such as at the dentist or during the medical care of Covid-19 patients."
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With over 30 years of writing and editing experience for newspapers, magazines and corporate communications, Kevin Kerfoot writes about natural health, nutrition, skincare and oral hygiene for Trusted Health Products’ natural health blog and newsletters.
Founder Ray Spotts has a passion for all things natural and has made a life study of nature as it relates to health and well-being. Ray became a forerunner bringing products to market that are extraordinarily effective and free from potentially harmful chemicals and additives. For this reason Ray formed Trusted Health Products, a company you can trust for clean, effective, and healthy products. Ray is an organic gardener, likes fishing, hiking, and teaching and mentoring people to start new businesses. You can get his book for free, “How To Succeed In Business Based On God’s Word,” at www.rayspotts.com.