Mouthwashes Have Antiviral Effect On SARS-CoV-2, May Suppress Covid-19: Study

Low concentrations of a particular compound in commercial mouthwashes suppress the infectivity of four variants of SARS-CoV-2.

Mouthwashes available in the market contain antibiotic and antiviral components that act against microorganisms in the mouth. One of these components is cetylpyridinium chloride. The compound has been found to reduce the viral load of SARS-CoV-2 in the mouth. ( Image Source :kreatikar/Pixabay )

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), or novel coronavirus, is the causative organism of Covid-19. The virus is airborne, and transmitted via aerosols, which are spread from the oral and nasal cavities. Not only does SARS-CoV-2 infect cells in the respiratory tract, but also the cells along the lining of the mouth and the salivary glands. Mouthwashes have an antiviral effect on SARS-CoV-2 and may suppress Covid-19, a new study reports. 

This is because some mouthwashes contain the chemical cetylpyridinium chloride, low concentrations of which have an antiviral effect on the novel coronavirus. The study, led by researchers at Hokkaido University, Japan, was recently published in the journal Scientific Reports. 

Which compound in mouthwashes suppresses SARS-CoV-2?

Mouthwashes available in the market contain antibiotic and antiviral components that act against microorganisms in the mouth. One of these components is cetylpyridinium chloride. The compound has been found to reduce the viral load of SARS-CoV-2 in the mouth, by disrupting the lipid membrane surrounding the virus. 

The advantage of cetylpyridinium chloride over other chemicals with similar effects is that it is tasteless and odourless. 

How does the compound work against the novel coronavirus?

The scientists studied the effects of cetylpyridinium chloride in Japanese mouthwashes, which typically contain a fraction of the compound compared to previously tested mouthwashes. The researchers studied the effects of cetylpyridinium chloride on cell cultures that express trans-membrane protease serine 2 (TMPRSS2). This is required for SARS-CoV-2 entry into the cell. 

The researchers tested four variants of SARS-CoV-2, namely alpha, beta, gamma and the wild strain. The effects of cetylpyridinium chloride were found to be similar across all the strains. 

They observed that within 10 minutes of application, thirty to fifty micrograms per millilitre of cetylpyridinium chloride inhibited the infectivity and capability for cell entry of SARS-CoV-2, the study says. Also, commercially available mouthwashes that contain cetylpyridinium chloride performed better than the compound alone. 

The researchers showed that saliva did not alter the effects of cetylpyridinium chloride. 

The study authors are currently assessing the effect of mouthwashes with this compound on viral loads in saliva of Covid-19 patients. Low concentrations of cetylpyridinium chloride in commercial mouthwashes suppress the infectivity of four variants of SARS-CoV-2, the study concludes.