Mouthwashes, oral rinses may inactivate human coronaviruses, study finds


Date:
October 19, 2020
Source:
Penn State
Summary:
Certain oral antiseptics and mouthwashes may have the ability
to inactivate human coronaviruses, according to a new study. The
results indicate that some of these products might be useful for
reducing the viral load, or amount of virus, in the mouth after
infection and may help to reduce the spread of SARS-CoV-2, the
coronavirus that causes COVID-19.



FULL STORY ========================================================================== Certain oral antiseptics and mouthwashes may have the ability to
inactivate human coronaviruses, according to a Penn State College of
Medicine research study. The results indicate that some of these products
might be useful for reducing the viral load, or amount of virus, in the
mouth after infection and may help to reduce the spread of SARS-CoV-2,
the coronavirus that causes COVID- 19.


========================================================================== Craig Meyers, distinguished professor of microbiology and immunology and obstetrics and gynecology, led a group of physicians and scientists who
tested several oral and nasopharyngeal rinses in a laboratory setting
for their ability to inactivate human coronaviruses, which are similar in structure to SARS-CoV-2. The products evaluated include a 1% solution of
baby shampoo, a neti pot, peroxide sore-mouth cleansers, and mouthwashes.

The researchers found that several of the nasal and oral rinses had a
strong ability to neutralize human coronavirus, which suggests that these products may have the potential to reduce the amount of virus spread by
people who are COVID-19-positive.

"While we wait for a vaccine to be developed, methods to reduce
transmission are needed," Meyers said. "The products we tested are readily available and often already part of people's daily routines." Meyers
and colleagues used a test to replicate the interaction of the virus
in the nasal and oral cavities with the rinses and mouthwashes. Nasal
and oral cavities are major points of entry and transmission for human coronaviruses.

They treated solutions containing a strain of human coronavirus, which
served as a readily available and genetically similar alternative for SARS-CoV-2, with the baby shampoo solutions, various peroxide antiseptic
rinses and various brands of mouthwash. They allowed the solutions to
interact with the virus for 30 seconds, one minute and two minutes, before diluting the solutions to prevent further virus inactivation. According to Meyers, the outer envelopes of the human coronavirus tested and SARS-CoV-2
are genetically similar so the research team hypothesizes that a similar
amount of SARS-CoV-2 may be inactivated upon exposure to the solution.

To measure how much virus was inactivated, the researchers placed the
diluted solutions in contact with cultured human cells. They counted
how many cells remained alive after a few days of exposure to the viral solution and used that number to calculate the amount of human coronavirus
that was inactivated as a result of exposure to the mouthwash or oral
rinse that was tested. The results were published in the Journal of
Medical Virology.

The 1% baby shampoo solution, which is often used by head and neck
doctors to rinse the sinuses, inactivated greater than 99.9% of human coronavirus after a two-minute contact time. Several of the mouthwash
and gargle products also were effective at inactivating the infectious
virus. Many inactivated greater than 99.9% of virus after only 30 seconds
of contact time and some inactivated 99.99% of the virus after 30 seconds.

According to Meyers, the results with mouthwashes are promising and add to
the findings of a study showing that certain types of oral rinses could inactivate SARS-CoV-2 in similar experimental conditions. In addition
to evaluating the solutions at longer contact times, they studied over-the-counter products and nasal rinses that were not evaluated in
the other study. Meyers said the next step to expand upon these results
is to design and conduct clinical trials that evaluate whether products
like mouthwashes can effectively reduce viral load in COVID-19-positive patients.

"People who test positive for COVID-19 and return home to quarantine
may possibly transmit the virus to those they live with," said Meyers,
a researcher at Penn State Cancer Institute. "Certain professions
including dentists and other health care workers are at a constant
risk of exposure. Clinical trials are needed to determine if these
products can reduce the amount of virus COVID- positive patients or
those with high-risk occupations may spread while talking, coughing or sneezing. Even if the use of these solutions could reduce transmission
by 50%, it would have a major impact." Future studies may include a
continued investigation of products that inactive human coronaviruses and
what specific ingredients in the solutions tested inactivate the virus.

Janice Milici, Samina Alam, David Quillen, David Goldenberg and Rena
Kass of Penn State College of Medicine and Richard Robison of Brigham
Young University also contributed to this research.

The research was supported by funds from Penn State Huck Institutes for
the Life Sciences. The researchers declare no conflict of interest.


========================================================================== Story Source: Materials provided by Penn_State. Note: Content may be
edited for style and length.


========================================================================== Journal Reference:
1. Craig Meyers, Richard Robison, Janice Milici, Samina Alam,
David Quillen,
David Goldenberg, Rena Kass. Lowering the transmission and spread
of human coronavirus. Journal of Medical Virology, 2020; DOI:
10.1002/ jmv.26514 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/10/201019125503.htm

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