SARS-CoV-2, the virus that causes COVID-19, is an airborne disease transmitted via aerosols, which are spread from the oral and nasal cavities—the mouth and the nose. In addition to the well-known division and spread of the virus in the cells of the respiratory tract, SARS-CoV-2 is also known to infect the cells of the lining of the mouth and the salivary glands. Commercially available mouthwashes contain a number of antibiotic and antiviral components that act against microorganisms in the mouth. One of these, cetylpyridinium chloride (CPC), has been shown by a team of researchers led by Professor Kyoko Hida to...