Social and news media are abuzz again following a new study suggesting that a common antimicrobial ingredient in over-the-counter mouthwash could kill the coronavirus in 30 seconds.
Not so fast, doctors say.
For one thing, the findings of the pre-print study haven’t actually been tested on humans or been reviewed by the broader scientific community.
More importantly: Nowhere does the study suggest that mouthwash could cure – or even prevent – you from getting COVID-19.
It was first suggested five months ago that mouthwash could perhaps be effective against SARS-CoV-2, the virus that causes COVID-19. Last week, researchers from Cardiff University in Wales published a study that got some people excited again.
Those folks don’t include physicians, who aren’t rushing to prescribe a daily rinse to lessen people’s chances of catching or transmitting the virus.
There are several reasons, according to health.com.
For starters, the results were reached in vitro and not outside a lab.
"It's interesting,” Dr. William Schaffner, an infectious disease specialist and professor at the Vanderbilt University School of Medicine, told health.com, “but this hasn't been studied in real life.”
As if that weren’t enough, the researchers cited "demonstrated a wide spectrum of inactivation ability" (in other words: some working, some not) among seven different mouthwashes tested: Corsodyl, Dentyl Dual Action, Dentyl Fresh Protect, Listerine Cool Mint, Listerine Advanced Gum Treatment, SCD Max, and Videne.
There’s no way of knowing for sure whether any mouthwash could possibly kill the virus without actually testing it on humans, as the study suggests, health.com noted.
Even if it did, where's the value?
Killing SARS-CoV-2 on contract isn’t that difficult. Alcohol, chlorhexidine and hydrogen peroxide have all done it, in fact. That doesn’t mean they can stop the source.
The damage has already begun once the virus is in your body, replicating itself in the nose, sinuses, throat, bronchial tubes and lungs -- especially if you’ve inhaled it, doctors say.
"Some brands of mouthwash can eliminate certain microbes for a few minutes in the saliva in your mouth,” The World Health Organization (WHO) said. “However, this does not mean they protect you from infection."
A virus or bacteria will grow back fairly quickly, experts say.
"You can't sterilize your mouth,” Dr. Graham Snyder, associate professor in the Division of Infectious Diseases at the University of Pittsburgh School of Medicine, told CNN. “The virus will continue to replicate.”
Listerine itself warns on its website that its mouthwash “has not been tested against any strains of coronavirus."
"Only some Listerine mouthwash formulations contain alcohol, and if present is only around 20% alcohol,” the company says. Listerine mouthwash is not intended to be used, nor would it be beneficial as a hand sanitizer or surface disinfectant."
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