Some over‐the‐counter mouthwashes, gargles, and nasal rinses can make human coronaviruses inactive, a study found.
These products seem to lower the amount of virus (viral load) in an infected person’s mouth and so reduce the transmission of SARS-CoV-2, which is responsible for COVID-19.
Oral and nasal cavities are the major entry points and spreaders of human coronaviruses.
Professor Craig Meyers and his team tested several nasal rinses and mouthwash gargling products for their level of protection against human coronaviruses.
The mouthwashes included were Peroxide Sore Mouth Cleanser, Hydrogen peroxide diluted to 1.5 percent in PBS solution, Listerine and Orajel Antiseptic Rinse.
The nasal rinses were Neti Pot solution (made based on manufacturer’s instructions), Johnson’s Baby Shampoo diluted to 1 percent in PBS solution.
Some of these products were able to neutralize the human coronavirus, suggesting their potential ability to reduce virus spread by COVID-19 patients.
Professor Meyers said:
“While we wait for a vaccine, methods to reduce transmission are needed.
The products we tested are readily available and often already part of people’s daily routines.”
They tested those products on a human coronavirus genetically similar to SARS-CoV-2 in a laboratory, the contact time with the virus was 30 seconds, one minute, and two minutes.
The 1 percent baby shampoo solution during the two-minute contact time was able to inactivate more than 99.9 percent of the virus whereas the over‐the‐counter saline nasal rinse and Neti Pot had no effect on the virus.
Also several over‐the‐counter antiseptic mouth washes with alcohol‐based eucalyptol, menthol, methyl salicylate, and thymol formulations were able to inactivate 99.9 percent of infectious virus.
Another study has suggested that chemicals such as ethanol, cetylpyridinium, and povidone-iodine commonly found in dental mouthwashes can destroy the outer shell of fat of many enveloped viruses.
These experimental findings show that certain types of oral rinses such as Listerine antiseptic have the inactivating properties which can be highly effective on reducing the viral load of SARS-CoV-2 even outside the lab.
Professor Meyers said:
“People who test positive for COVID-19 and return home to quarantine may possibly transmit the virus to those they live with.
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.”
The study was published in the Journal of Medical Virology (Meyers et al., 2020).