Recently a study on COVID-19 has shown that human coronaviruses are inactivated after 30 seconds of exposure to Listerine™ mouthwash. Is this a breakthrough, or just another false hope like hydroxychloroquine? Let’s break it down.
The study researched the effects of assorted nasal rinses and mouthwash products on the infectivity of human coronaviruses. Listerine Antiseptic showed promising results, with a >99.99% inactivation rate, even with the short exposure time of 30 seconds. Other mouthwash products showed excellent results.
However, something to understand is that the study did not use SARS-CoV-2, the strain responsible for COVID-19, but a close relative. They are structurally similar, as they both have the distinct “crown” that corona takes its name from. It is currently unknown whether the difference between the surrogate virus and the real virus is significant.
If the difference between the two is significant, then unfortunately this study has no application on the current crisis. However, if the difference between the two is not, this is an important part in our fight against corona.
Another possible problem is the nature of the human mouth. The tests were conducted on cells separate from the body, in environments that only partially mirror that which is found in the mouth. The mouth is a changing environment, as it differs from person to person, and what this person has put in their mouth at that time.
This probably won’t matter too much though, as if mouthwash is used properly, it will show similar results as seen in the studies. There is a key problem here though. Does cleaning out COVID in the mouth prevent spreading of the virus?
The answer is probably no. If the virus is already in the respiratory system, cleaning the mouth doesn’t stop it from exiting through the mouth. Should you buy mouthwash to prevent COVID? Probably not. The best that we can do now is socially distance, weak masks, and keep good hygiene practices. Fresh breath won’t hurt either.