Can Mouthrinse Kill the Coronavirus?

University of North Carolina (UNC) at Chapel Hill Adams School of Dentistry researchers are investigating how effective mouthrinse is at reducing a person’s risk of spreading COVID-19 through a two-part clinical trial that will test the utility of commercially available oral rinses in limiting SARS-CoV-2 infectivity. Identifying an oral rinse with antiviral efficacy against SARS-CoV-2 has wide implications in dentistry and other close contact situations where masks need to be removed. 

In dentistry, where dental handpieces, ultrasonic scalers, and air-water syringes generate aerosols that can stay in the air for hours, finding an effective preprocedural oral rinse for use before dental treatment can greatly reduce the risk of viral transmission. “We are hoping to find an oral rinse that reduces viral load, viral replication and salivary infectivity for at least 30 minutes—the time of a social interaction or healthcare visit,” the authors note. 

A total of 260 participants will be enrolled in the clinical trial led by Laura Jacox, DMD, PhD, MS, an assistant professor at UNC Adams School of Dentistry, and Jennifer Webster-Cyriaque, DDS, PhD, a professor in the divisions of Craniofacial and Surgical Care, Oral and Craniofacial Sciences, and the Department of Microbiology and Immunology, School of Medicine.

In the first study, patients recently infected with the virus will be randomized to one of six commercially available mouthrinses, each with a different active ingredient, and be asked to provide a saliva sample before and after rinsing for 60 seconds. Saliva samples will be collected from patients at 15-minute intervals over the course of an hour. The second study is similar, but requires an at-home component in which participants use mouthwashes for seven days and return to the lab for an in-person visit. Study participants will also complete a short survey on the taste and experience of using the mouthrinse.

Investigators will use the samples to measure the saliva’s viral load, viral replication, and infectivity. An assay will be used to test how infectious the saliva is, and if the salivary virus is able to infect cells.

Previous studies have demonstrated how specific mouthrinse agents can penetrate lipid membranes of other viruses and how the use of an antimicrobial preprocedural mouthrinse reduces the transmission of oral pathogen. Findings from research led by UNC Adams School of Dentistry and National Institutes of Health have also found that SARS-CoV-2 infects cells in the mouth. 

If a mouthrinse is found to be effective in lowering infectivity, people could essentially rinse with the identified mouthrinse before situations where masks cannot be worn or where social distancing is not possible to decrease the potential for transmission. 

“Together with the existing tools to mitigate the virus, mouthrinses can add an additional layer of protection. They are widely accessible, inexpensive, and U.S. Food and Drug Administration-approved products that everyone can purchase at their local drugstore,” says Jacox, the study’s lead investigator and an orthodontist at Severt Smiles Orthodontics in Chapel Hill and Pittsboro, North Carolina. “If the study identifies an oral rinse effective at reducing salivary infectivity and viral load, the rinse could be widely adopted in a myriad of settings, from restaurants to the dental office. Applications are endless.”

Researchers anticipate having preliminary results by summer.