Mouthwash May Inactivate Human Coronaviruses, Help Reduce Spread of COVID-19
Certain oral antiseptics and mouthwashes can inactivate human coronaviruses, according to a research study by Penn State College of Medicine. The results suggest that some of these products might be useful in lowering the viral load or the amount of virus in the mouth after infection and in reducing the spread of SARS-CoV-2, the coronavirus that causes COVID-19.
Craig Meyers, eminent professor of microbiology and immunology and obstetrics and gynecology, led a group of doctors and scientists who tested several oral and nasopharyngeal douches in a laboratory for their ability to inactivate human coronaviruses, which are similar in structure to SARS-CoV Are 2. Products reviewed include a 1% solution of baby shampoo, a neti pot, peroxide mouth pain cleanser, and mouthwashes.
The researchers found that several of the nasal washes and mouthwashes had a strong ability to neutralize the human coronavirus, suggesting that these products may have the potential to reduce the amount of virus spread by COVID-19 positive people.
“While we wait for a vaccine to be developed, methods to reduce transmission are needed,” Meyers said. “The products that we have tested are readily available and are often part of everyday life.”
Meyers and colleagues used a test to replicate the interaction of the virus in the nasal and oral cavities with the rinses and mouthwashes. The nasal and oral cavities are important entry and transmission points for human coronaviruses. They treated solutions containing a strain of the human coronavirus that served as a readily available and genetically similar alternative for SARS-CoV-2 with baby shampoo solutions, various peroxide antiseptic washes, and various brands of mouthwash. They let the solutions interact with the virus for 30 seconds, one minute and two minutes before diluting the solutions to prevent further inactivation of the virus. According to Meyers, the outer sheaths 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 can be inactivated upon exposure to the solution.
To measure how much virus was inactivated, the researchers put the diluted solutions in contact with cultured human cells. They counted how many cells remained alive after a few days of exposure to the virus solution and used that number to calculate the amount of human coronavirus that became inactivated as a result of exposure to the mouthwash or mouthwash tested. The results were published in the Journal of Medical Virology.
The 1% baby shampoo solution, often used by head and neck doctors to rinse the sinuses, inactivated more than 99.9% of the human coronavirus after a two-minute contact time. Some of the mouthwash and gargle products were also effective in inactivating the infectious virus. Many inactivated more than 99.9% of the virus after just 30 seconds of contact time, and some inactivated 99.99% of the virus after 30 seconds.
Meyers said the results with mouthwashes are promising and complement the results of a study showing that certain types of mouthwashes can inactivate SARS-CoV-2 under similar experimental conditions. In addition to evaluating the solutions for longer contact times, they examined over-the-counter products and nasal rinses that were not evaluated in the other study. According to Meyers, the next step in expanding these findings will be to design and conduct clinical trials that will evaluate whether products like mouthwash can be effective in reducing viral loads in COVID-19 positive patients.
“People who test positive for COVID-19 and who go back to quarantine may have the potential to spread the virus to those they live with,” said Meyers, a researcher at Penn State Cancer Institute. “Certain professions, including dentists and other healthcare workers, are at constant risk of exposure. Clinical studies are needed to determine whether these products can reduce the number of COVID-positive patients or whether high-risk patients can spread while speaking, coughing, or sneezing. Even if using these solutions could reduce transmission by 50%, it would have a significant impact. “
Future studies could include continued investigation of products that contain inactive human coronaviruses and what specific ingredients in the solutions tested will inactivate the virus.
Reference: “Reducing the Transmission and Spread of the Human Coronavirus” by Craig Meyers, PhD; Richard Robison, PhD; Janice Milici, BS; Samina Alam, PhD; David Quillen, MD; David Goldenberg, MD, FACS and Rena Kass, MD, September 17, 2020, Journal of Medical Virology.
DOI: 10.1002 / jmv.26514
Janice Milici, Samina Alam, David Quillen, David Goldenberg, and Rena Kass of Penn State College of Medicine, and Richard Robison of Brigham Young University also contributed to this research.
The research was supported by funding from the Penn State Huck Institute for the Life Sciences. The researchers do not declare a conflict of interest.