Mouthwashes that contain cetylpyridinium chloride (CPC) have been found to reduce by at least one thousand times the infectivity of SARS-CoV-2 (Covid-19) in vitro. Researchers in Spain tested CPC-containing mouthwashes against variants of SARS-CoV-2, including the Alpha variant, and said that such mouth rinses could constitute a cost-effective measure to aid in the reduction of viral transmission.

In the study, the researchers pointed out that cases with a higher SARS-CoV-2 viral load in the saliva are associated with higher transmission rates of the virus. They said that, if proved effective in reducing the SARS-CoV-2 viral load, the use of easily obtainable at-home oral care products could represent a globally accessible and cost-effective measure to disrupt the viral transmission chain.

The study focused on the effect of CPC, which has previously been shown to exhibit antiviral activity against viruses such as the influenza viruses. The researchers tested three Dentaid CPC-containing mouthwashes with different intended uses. The CPC-containing mouthwashes were compared with vehicles containing the same respective formulation without CPC, and it was found that the CPC-containing mouthwashes disrupted the integrity of the viral membrane and inhibited the entry of SARS-CoV-2 into target cells.

The researchers wrote: “CPC has antiviral activity against different variants of SARS-CoV-2, and this compound exerts its activity by blocking viral entry by inhibiting viral fusion on target cells. CPC acts by disrupting the integrity of the viral envelope, as previously shown for influenza virus […] and it equally affects distinct SARS-CoV-2 variants”.