- New research examined if mouthwashes, antiseptics, and a nasal rinse were effective ways to kill a virus very similar to COVID-19.
- The study found that some of these products can be effective against a type of human coronavirus under lab-controlled conditions.
- However, experts say human trials with people with COVID-19 are needed to confirm how effective they would be at reducing the spread of the virus between people.
- Experts also say that mouthwash or nasal rinses are no substitute for using a mask to prevent the spread of COVID-19.
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A new study from Penn State University suggests that commonly available oral antiseptics, mouthwashes, and nasal rinses might inactivate human coronaviruses, reducing risk of transmission.
“We were looking for a simple over-the-counter (OTC) procedure to lower the transmission of coronavirus,” study author Craig Meyers, PhD, and a professor at Penn State University told Healthline. “A procedure that did not differ from the standard use.”
The findings indicate that some OTC products may be effective at reducing the amount of coronavirus present in people’s mouths — potentially reducing spread of the virus that causes COVID-19.
The study was
According to Meyers, the results were surprising on two counts, “The first was how well certain products inactivated the virus. Second, how some products, those containing 1.5 percent hydrogen peroxide, had no effect.”
“It definitely is an eye-opener,” agreed Dr. Nikhil Bhayani, an infectious disease physician with Texas Health Resources.
While the nasal and oral cavities are major points of entry and transmission for coronaviruses, Meyers and team used a test to replicate how the virus interacted with rinses and mouthwashes.
The virus analyzed was human coronavirus 229e (HCoV-229e) and not the novel coronavirus SARS-CoV-2 that causes COVID-19. There were also no human participants involved in this research.
This study consisted of treating solutions that contained HCoV-229e, which was readily available and genetically similar to SARS-CoV-2.
Researchers introduced different hydrogen peroxide antiseptic rinses and various brands of mouthwash into the coronavirus solution and allowed them to interact with the virus for 30 seconds, 1 minute, and 2 minutes, before they diluted the solution to prevent any further virus deactivation.
Meyers’ findings add to previous research looking at how effective oral rinses can be to inactivate human coronavirus.
Although that study, published in The Journal of Infectious Diseases, also relied on lab-controlled conditions and didn’t specifically investigate SARS-CoV-2.
However, Meyers and team used longer contact times and OTC nasal and oral rinses not evaluated before, and he considers human trials on COVID-19-positive patients essential to confirm the findings.
“With this said, human clinical trials are still needed,” said Meyers. “But again the data suggests that we do something we already should probably [be] doing that is simple and safe.”
Those clinical trials are currently underway.
According to Bhayani, while he thinks the findings are plausible, there are important questions that need to be answered, such as: At what stage of infection would oral or nasal rinses reduce the risk of transmission?
Strangely, a baby shampoo-based nasal rinse showed significant virus-killing ability.
“A 1% baby shampoo nasal rinse solution inactivated HCoV greater than 99.9% with a 2‐min contact time,” the study authors wrote.
The OTC mouthwash/gargle products investigated included Listerine and Listerine-like products which were “highly effective at inactivating infectious virus with greater than 99.9% even with a 30‐s [second] contact time.
The Penn State researchers also pointed to
When asked if antiseptics that kill coronaviruses in the mouth, throat, and nasal cavity could help delay or even prevent infection by SARS-CoV-2, Bhayani agreed that it might help “reduce the viral burden lowering the risk of transmission.”
Finally, researchers put the solutions in contact with cultured human liver cells and waited a few days to see how many of these cells were still alive to calculate the percent of human coronavirus made harmless from exposure to mouthwash or nasal rinse.
However, these results were the result of controlled lab conditions using a different type of coronavirus than SARS-CoV-2. The true effectiveness of these antiseptics in humans with the novel coronavirus can’t be firmly decided this way.
“This is not a replacement for masks or distancing,” insisted Meyers. “It is another layer to preventing the spread.”
He explained that for those who are positive and go home to quarantine “it could help protect those they live with,” and could also provide another layer of protection to healthcare providers at high risk of infection.
“Even if the use of these solutions could reduce transmission by 50 percent, it would have a major impact,” Meyers said in a statement.
Researchers investigated different OTC mouthwashes, antiseptics, and a nasal rinse to find how effective they are at rendering a virus very similar to SARS-CoV-2 harmless.
While study findings suggest that some OTC products can be effective against a human coronavirus, reducing risk of infection or transmission, human trials with COVID-19-positive patients are needed to confirm how effective they can be against the novel coronavirus.
Experts say while the idea is plausible, more research is needed to confirm the findings. They also say that mouthwash or nasal rinse is no substitute for using a mask to prevent the spread of COVID-19.