Antiseptic mouthwash ingredients also have virucidal properties that may reduce the viral load in the droplets delivered by patients infected with Sars-CoV-2 coronavirus. But is this theoretical effect sufficient to represent a real means of prevention?
What if a good mouthwash could give us fresh, virus-free breath? This hypothesis is put forward in a new study published in the medical journal Fonction on 14 May 2020. The researchers examined the effect of the main ingredients in mouthwashes (ethanol, chlorhexidine, cetylpyridinium chloride, hydrogen peroxide, and povidone-iodine) on viruses.
“Sars-CoV-2″ is an enveloped virus characterized by an outer lipid membrane originating from the host cell from which it is derived. However, existing mouthwash formulations interfere with this lipid membrane,” explain the authors, who call for a clinical evaluation of these products as a means of prevention.
The throat and saliva, sites of high coronavirus replication
“Previous studies have shown that the throat and salivary glands are sites of virus replication and transmission in the early phase of COVID 19 disease and in asymptomatic patients,” the authors said. Studies have shown that virus particles can survive up to three hours in the air in aerosol form. Therefore, scientists believe that a healthy person could theoretically become infected by inhaling contaminated droplets when a person carrying the virus coughs or speaks.
Hence the idea of reducing the viral load in the mouth by using mouthwashes to limit the transmission of the virus. “The CDC recommends that patients rinse their mouths before going to the dentist to reduce the risk of transmission,” said Valerie O’Donnell, head of the Department of Infection and Immunity at Cardiff University and co-author of the study.
Alcohol can temporarily kill the virus on oral surfaces, as would a glass of vodka, whiskey, rum, and tequila.
But we still have a long way to go before a mouthwash makes a mask unnecessary. “In the short term, these products could reduce the spread of the virus to close family contacts,” says Eric Bortzn, a biologist at the University of Alaska Anchorage. Alcohol can temporarily kill the virus on oral surfaces, just like a glass of whiskey, rum, or tequila,” Bortzn said. “But in a highly infected person, the infected pharyngeal cells may also produce more virus,” he added. And the mouth is not the only place where the virus is transmitted. The nose and throat are also important places where the virus multiplies and spreads.
A special anti-COVID mouthwash
The virucidal effect of mouthwashes has only been demonstrated in vitro. Therefore, testing under real conditions is essential to determine whether mouthwashes can actually prevent the spread of the coronavirus, the authors of the British study themselves stress. “These tests could include existing products or formulations specifically designed against sars-cov2, they suggest. This is an under-researched area with significant clinical need.”
In the meantime, the use of the mask in confined or high-density areas remains strongly recommended. To remove any ambiguity, the manufacturer of Listerine® mouthwash has in fact posted a warning on its website stating that its product “has not been tested for coronavirus and that we should follow WHO prevention measures: wash hands, maintain social distance, and avoid touching your mouth and nose.