In vitro assessment of the virucidal activity of four mouthwashes containing Cetylpyridinium Chloride, ethanol, zinc and a mix of enzyme and proteins against a human coronavirus

Background saliva is established to contain high counts SARS-CoV-2 virus and contact with saliva droplets, contaminated surfaces or airborne particles are sources of viral transmission. The generation of infective aerosols during clinical procedures is of particular concern. Therefore, a fuller understanding of the potential of mouthwash to reduce viral counts and modulate the risk of transmission in medical professional and public context is an important research topic.

Method we determined the virucidal activity of four anti-bacterial mouthwashes against a surrogate for SARS-CoV-2, Human CoV-SARS 229E, using a standard ASTM suspension test, with dilution and contact times applicable to recommended mouthwash use.

Results the mouthwash formulated with 0.07% Cetylpyridinium Chloride exhibited virucidal effects providing a ≥3.0 log reduction HCoV-229E viral count. Mouthwashes containing 15.7% ethanol, 0.2% zinc sulphate heptahydrate and a mix of enzymes and proteins did not demonstrate substantive virucidal activity in this test.

Conclusion mouthwash containing 0.07% Cetylpyridinium Chloride warrants further laboratory and clinical assessment to determine their potential benefit in reducing the risk of SARS-CoV-2.

Highlights SARS-CoV-2 can be transmitted through contact with infective saliva.

Studies are needed to understand if mouthwash can lower SARS-CoV-2 transmission risk.

0.07% Cetylpyridinium Chloride (CPC) mouthwash exhibited virucidal effects against HCoV-SARS 229E.

Further studies on potential of 0.07% CPC mouthwash against SARS-CoV-2 are warranted.