Gargling Mouthwash Won't Prevent COVID Infection

According to Misbar’s investigation, the social media claims about mouthwash are most likely referring to the findings of a study published in the Journal of Medical Virology. In this study, researchers from Penn State University tested several mouth and sinus rinses in a lab setting to determine their ability to inactive human coronaviruses. The viruses tested are similar in structure to SARS-Cov-2. The researchers found several of the nasal and mouth rinses had a strong ability to neutralize human coronavirus. 

In the lab, the researchers treated solutions containing a strain of human coronavirus with baby shampoo, peroxide antiseptic rinses, and mouthwashes. They allowed the solutions to interact with the virus for 30 seconds, one minute, and two minutes. The Listerine-type mouthwashes reduced the viruses in the solution by greater than 99 percent. 

The research on mouthwash is promising but was not conducted on people with COVID-19, only on laboratory solutions containing a similar virus. The study was also limited to the virus in the nose and mouth, and not in the rest of the body. The scientists were not trying to determine if the rinses would ward off COVID-19, but rather, if gargling would have the potential to inactivate the virus once is was already present and possibly make sick people less infectious. 

While preliminary research is showing mouthwash and sinus rinses may reduce viruses in the mouth and nose, mouthwash will not ward off COVID-19.