Cetylpyridinium chloride mouthwashes: Potential role in COVID-19 control.

To the Editor:

We have read with great interest the article by Komine et al. [1] published in volume 33 of 2021 of the journal about the in vitro virucidal activity against SARS-COV-2 of oral health care products. In this publication, the authors suggest that Cetylpyridinium Chloride (CPC) has antiviral activity against SARS-COV-2, also recommend its use through mouthwashes.

Mouthwashes are oral antiseptics commonly used as antimicrobial chemical agents, which can be classified by their chemical structure into phenols, oxidising agents (hydrogen peroxide), biguanides (chlorhexidine), and quaternary ammonium compounds (Cetylpyridinium Chloride). Some compounds such as Cetylpyridinium Chloride (CPC) inactivate viruses by breaking their lipid envelope, thus interfering with their ability to enter the cell; this would help reduce the salivary viral load, so the risk of transmission would be lower and the severity of the disease would also be reduced [[2], [3], [4], [5]].

Despite the exhaustive recommendations on basic hygiene and personal protection measures and immunisation carried out in countries with high transmissibility of the virus [6], the use of CPC-based mouthwashes has not spread as a complementary mechanism, despite its high preventive potential and mitigating [2].

Other authors [3,7] have suggested the use of mouthwashes before any procedure that generates aerosols, such as dental care; however, official recommendations on the use of mouthwashes that contribute to the prevention or attenuation of COVID-19 in the population have not yet been published.

Two clinical trials have been documented, the first is a randomised controlled clinical trial [2], in which they conclude that commercial mouthwashes formulated with CPC could reduce the viral load of SARS-COV-2 more consistently than other mouthwashes, bringing to light the potential role of this component in the control of COVID-19. And the second clinical trial [8], a pilot study, which also suggests using CPC as a mouthwash against SARS-COV-2.

Mouthwashes with CPC are low-cost, clinically safe and easily accessible products for the general public, with an in vitro antiviral effect superior to chlorhexidine [1,7]; similarly, CPC could be added to body disinfectants to decrease the amount of virus spread [9]. On the other hand, the recommendations made by governments and healthcare providers need to be based on complete and conclusive evidence, so that the use of this type of product can be massively communicated. Despite this, there is currently a lack of publications on studies related to the use of this compound to reduce the viral load of SARS-COV-2.

In conclusion, we support the claims made by Komine, although there is sufficient in vitro evidence [1,7], it is necessary that the scientific community, in addition to the pharmaceutical industries, carry out more observational and experimental studies, which allow strengthening the evidence of the virucidal effect of CPC against SARS-COV-2, complementing and correcting the limitations of preliminary studies [1,2,5,8]; in order to reduce the impact of this disease on our society.