Dental School Studying Mouthwash Against COVID-19

Posted on Feb. 24, 2021

Researchers at UNC’s Adams School of Dentistry have launched a clinical trial to test whether mouthwash can reduce a person’s risk of spreading coronavirus.

Lab experiments have shown mouthwash can kill coronaviruses quickly, but there’s no evidence mouthwash can prevent the virus from infecting people. The school is investigating how well mouthwash works to reduce the amount of coronavirus in the mouths of those with COVID-19 and whether it can lessen the chance of spreading the virus to others.

The focus of the research is to find a way to lower the risk of coronavirus transmission in situations where masking and being more than 6 feet apart might not be an option, for instance, during dental procedures.

“While we are excited about the bench-top data, the true test is whether these mouthwashes have effect on saliva in patients’ mouths and whether a mouth rinse could reduce the risk of SARS-CoV-2 transmission through oral droplets,” said principal investigator Dr. Laura Jacox ’19 (MS), an orthodontist and oral health sciences researcher who is director of the Orthodontic Research Program at the dental school.

Specifically, researchers plan to measure how much SARS-CoV-2 is found in saliva before and after using mouthwash according to the directions on the label. People over age 18 who have tested positive for COVID-19 within the previous week are eligible to participate in the clinical trial.

Because the mouth continually makes saliva, samples will be collected and tested every 15 minutes, for up to an hour, to track how long any reduction in viral load and infectivity — defined as the ability to produce or transmit infection — lasts.

The clinical trial will test commercially available mouthwashes that contain common antiseptic ingredients, such as cetylpyridinium chloride or ethanol.

“The study will allow us to determine which active ingredient in mouthwash has the most promise,” Jacox said. “Ideally, it is an ingredient that is already FDA-approved so it can go into use immediately.”

If proven effective, mouthwash could be a tool in controlling the spread of COVID-19 at one of the body’s primary points of coronavirus entry and transmission. Preliminary results of a study led by the dental school and the National Institutes of Health showed the salivary glands, tongue and tonsils, in particular, are vulnerable to coronavirus infection.

COVID-19 commonly spreads during close contact when an infected person coughs, talks, sneezes or sings.

“Using a mouth rinse is an easily implementable intervention that is low risk, inexpensive and holds the potential for high reward,” said Dr. Jennifer Webster-Cyriaque ’98 (PhD), a professor at the dental school and in the department of microbiology and immunology at UNC’s School of Medicine. “The potential benefit can reach far beyond dental care to educational settings and places of worship and help essential workers when close contact is unavoidable.”

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