No, mouthwash does not save you from the coronavirus

The provocative headline rash recently provided an intriguing idea that mouthwashes can help “inactivate” coronaviruses and limit their spread.

The story comes from a new study that found that the common cold-causing coronavirus, which does not cause Covid-19, can be incapacitated in the laboratory when given mouthwash. .. The authors of the study concluded that the products they tested “may provide an additional level of protection” against the new coronavirus.

However, outside experts have warned against over-interpreting the results of studies that may not be practically relevant to the new coronavirus that killed more than 220,000 Americans. Not only did the study not investigate this deadly new virus, but it also did not test whether mouthwash affects the way the virus spreads from person to person.

“I have no problem using Listerine,” said Angela Rasmussen, a virologist at Columbia University. “But it’s not an antiviral drug.”

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A study published last month Medical Virology JournalWe only examined the coronavirus called 229E, which causes the common cold. Called the official name of SARS-CoV-2, we did not look for a new coronavirus that causes a much more serious illness. After rigorous training, researchers can study SARS-CoV-2 only in highly secure laboratories.

The two viruses belong to the same family and, broadly speaking, appear to be anatomically similar. This makes the 229E a good proxy for SARS-CoV-2 in certain experiments. But the two viruses should not be considered compatible, Rasmussen said.

Researchers have found several, including a water-soaked mixture of Johnson’s baby shampoo (sometimes used to flush the inside of the nose), and mouthwashes with Listerine, Crest, Oragel, Eight, and CVS. We tested the virus-destroying effect of the product. They flooded the 229E coronavirus, which grew in human hepatocytes in the laboratory, with these chemicals for 30 seconds, 1 minute, or 2 minutes. It is longer than normal twigs and splits and penetrates the nose and mouth. According to this study, about 90% to 99% of the virus was unable to infect cells after this exposure.

“It’s clear that when these compounds come into contact with the virus, they can inactivate the virus,” said Craig Myers, a researcher at Pennsylvania State University, the author of this study.

However, other experts said the findings were of limited value to the real world, as the study did not recruit human volunteers to gargle the product in question. The human mouth, filled with corners and crevices, and the slurry of chemicals secreted by diverse cell stems are much more complex than inside a laboratory dish. Marika Marinis, an infectious disease expert at Yale University, said it should not be considered definitive “unless human studies are conducted.”

Myers said he hopes his team will start such a study soon, and that a few clinical trials have already begun investigating these questions.

The results of this study are not necessarily surprising or unprecedented. Other researchers have conducted similar experiments, including those investigating the effects of mouthwashes on the new coronavirus, with similar results. And since the early days of the pandemic, scientists have emphasized the effectiveness of hand washing and disinfection with soaps, alcohol, and other similar chemicals that can rupture the fragile outer layer or envelope of the new coronavirus. I did. (However, not all mouthwashes and nasal irrigators contain such powerful ingredients.)

Valerie Fitzhue, a pathologist at Rutgers University, pointed to a study in the 1990s when Texas researchers swirled and inactivated the flu virus with Listerine for 30 seconds. However, the study “has never been shown to be clinically relevant,” she said.

Even if people do the very thorough job of coating the inside of their mouth and nose with chemicals that kill the coronavirus, a significant amount of the virus will still remain in the body. The new coronavirus penetrates not only the mouth and nose, but also the deep throat and lungs, hoping that mouthwash and nasal wash will not enter.

Viruses that are already hidden inside the cells are also protected from the fast-acting chemicals contained in these products. “It’s not like your cells get infected, then they secrete a lot of viruses, and they’re done,” Rasmussen said. “Infected cells are constantly making more viruses. It’s a matter of timing.”

Relying on mouthwash and nasal irrigation to get rid of the infectious virus from the body is as wasteful as cutting the top of a herd of weeds, paying little attention to the roots, and expecting the pests in the garden to disappear.

Myers has acknowledged this limitation. After swirling the mouthwash quickly, he said, “How much do you have? I don’t know.” “What we’re saying now is that this could add a layer of protection,” he explained, in addition to proven protective measures such as wearing masks and physical distance. hand.