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Mouthwash May Help Inactivate Human Coronaviruses—But Not Necessarily COVID-19

mouthwash being poured into a cup

 Huizeng Hu / Getty Images

Key Takeaways

  • Research suggests mouthwash and other over-the-counter products can inactivate certain strains of coronavirus.
  • Listerine products seem to be the most effective, inactivating the most viral cells in the shortest period of time.
  • The study opens doors for clinical trials that will look at the effect these products have on human strains of SARS-CoV-2, the virus that causes COVID-19.

A recent study out of Penn State College of Medicine suggests mouthwash and other oral rinses may inactivate human coronaviruses. However, SARS-CoV-2, the virus that causes COVID-19, was not one of the coronaviruses tested.

The September study, published in the Journal of Medical Virology, took different over-the-counter rinses and cleaning products and combined them with a surrogate coronavirus strain. The products used included:

  • 1% solution of baby shampoo
  • Neti pot
  • Peroxide sore-mouth cleansers
  • Mouthwashes

The study found that several of these products were highly effective at inactivating infectious coronavirus cells. The 1% baby shampoo solution and Listerine products were particularly successful, inactivating 99.9% of the virus.

Researchers also discovered that the amount of time the virus cells spent in contact with these products —ranging from 30 seconds up to two minutes—varied their effectiveness at inactivating the virus. Listerine products in particular inactivated 99.9% of the virus within just 30 seconds, suggesting that commonly available healthcare products may contain certain properties with the capacity to destroy or inactivate viruses, according to the study.

While the study did not look directly at SARS-CoV-2, lead study author Craig Meyers, MS, PhD, a professor in the department of microbiology and immunology at Penn State, tells Verywell the surrogate coronavirus used in the study is very similar in cell structure to SARS-CoV-2— meaning results are still promising. A July study in Germany performed similar tests on SARS-CoV-2 and found similar results, suggesting that both strains respond well to over-the-counter products.

What This Means For You

Social distancing, mask-wearing, and handwashing continue to be the best practices for protecting yourself from COVID-19. More research needs to be done on the effectiveness of over-the-counter products before any recommendations can be made.

Mouthwash As a Complement to Safety Precautions

Respiratory droplets that enter the body via the nose or mouth are still the main form of transmission for COVID-19, Meyers tells Verywell. When people with COVID-19 cough, sneeze, talk, or breathe, they release infectious droplets that quickly facilitate the spread of the virus, according to the Centers for Disease Control and Prevention (CDC).

There is some evidence suggesting that under certain conditions, particularly in tight spaces with poor ventilation where particles can linger in the air for hours, COVID-19 be spread through airborne transmission. However, data still shows that coming in close contact with an individual who emits viral respiratory droplets is still the most common source of transmission.

Meyers’ research could provide an extra layer of protection toward that spread, he says.

“We’re not suggesting in any way that you should stop wearing your mask or social distancing,” Meyers says. “We’re hoping this will be another layer on top of that to prevent spread.”

The study's findings suggest that rinses could serve not as a replacement, but rather as a complement to other safety precautions. Meyers says this study fits into a previous body of literature looking at the role common disinfectants play in mitigating infections that, like COVID-19, enter the body via nasal and oral cavities. 

More Research Is Needed

These findings could have promising implications for individuals who have tested positive for COVID-19 and are quarantined near family members or other individuals. These over-the-counter products could be a means of lowering the viral load they can spread to others, Meyers says.

Additionally, in care facilities, where individuals are in crowded conditions, over-the-counter healthcare products could be used to lower the amount of spread.

“The goal [of the study] is lowering the transmission, not looking for a cure for the disease," Meyers says.

While the results of the study were promising, Meyers says clinical trials must be completed before experts start endorsing over-the-counter products and sending public messages about which products to buy.

After the study’s publication, some questioned its practical relevance because researchers examined a different strain of coronavirus and didn't include humans.

Meyers explains that it’s easy for there to be a disconnect between scientific research and the way it’s translated to the general public. While for scientists like Meyers, this study is clearly only a first step in a series of several future studies, headlines might cause the public to draw quick conclusions without fully understanding the context.

“People will read the title of the article, but they won’t read the article,” he says. He says the scientific community could do a better job of explaining the implications of their results to the general public.

This study, Meyers says, is just a beginning foundation for future studies. Human experiments are the next step. While he and his colleagues are gathering the resources to conduct a clinical trial, others are already being conducted across the country.

“We have a foundation of data that looks very compelling,” Meyers says. “Now we need to move to the clinical trials.”

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Article Sources
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  1. Meyers C, Robison R, Milici J et al. Lowering the transmission and spread of human coronavirus. J Med Virol. 2020. doi:10.1002/jmv.26514

  2. Meister TL, Brüggemann Y, Todt D, et al. Virucidal efficacy of different oral rinses against severe acute respiratory syndrome coronavirus 2. J Infect Dis. 2020;222(8):1289-1292. doi:10.1093/infdis/jiaa471

  3. Centers for Disease Control and Prevention. How COVID-19 spreads. Updated October 5, 2020.

  4. U.S. National Library of Medicine. Clinical trials.