A. TL,DR: Mouthwash won’t prevent or cure COVID-19.
Consistent with several prior studies, a recent laboratory-based study out of Cardiff University found that over-the-counter mouthwash (with active ingredient cetylpyridinium chloride [CPC]) will inactivate 90-99% of the coronavirus after a mere 30 seconds. Sounds exciting! …but don’t get your hopes up.
The clinical relevance of mouthwash for COVID-19 is limited.
1.) These mouthwash studies are conducted in labs, not in the mouths of humans. Human mouths are much more complex in shape, texture, and chemical composition than a petri dish. Humans may not swish as thoroughly or for as long as necessary to adequately reduce the viral load in the saliva.
2.) Even in the rare perfect-use scenario, regular rinsing of your mouth will not prevent you from contracting COVID-19 through your nasal passages.
3.) And if you already have COVID-19, mouthwash will eliminate the virus only in your saliva. It won’t have any effect on the virus that has spread to your respiratory tract or lungs.
Thus, mouthwash is not a prevention or treatment for COVID-19.
More research in humans is necessary to identify if mouthwash may help reduce the transmission to others by reducing viral load in the saliva, and how long the effect will last.
While there are oral hygiene benefits of using mouthwash, don’t count on gargling your way out of this disease. Of course, you can use mouthwash as a test for a loss of smell or taste. If your minty mouthwash falls flat, stay home to keep others safe.
In fact, given the widespread surge in case numbers, please stay home anyway. Mask up if you must go out, and avoid being indoors with people outside your household.
p.s. Nobody cares what your breath smells like on Zoom