Mouthwash against SARS-CoV-2? Unilever's 'very promising' prelim study opens door to more research

The personal care major told CosmeticsDesign-Europe it had now started a “long-term and robust programme of research”​ that built on this preliminary material. It hoped to carry out clinical studies starting next year.

Preliminary research findings ‘very promising’​

The preliminary in-vitro​ research was commissioned by Unilever Research and Development and conducted by US testing firm Microbac Laboratories on behalf of the personal care major.

Early-stage findings – not yet audited or peer-reviewed – suggested mouthwash containing Cetylpyridinium chloride (CPC) could play “an important role”​ as a preventative measure in reducing viral transmission of SARS-CoV-2 – the virus that caused COVID-19. The results indicated that 30 seconds of rinsing with a CPC mouthwash could potentially reduce viral load of SARS-CoV-2 by 99.9%.

Glyn Roberts PhD, head of oral care research and development at Unilever and joint lead author of the study, said: “While we are clear that this is not a cure or proven way to prevent the transmission of [SARS-CoV-2], the results are very promising, and given the critical stage of the pandemic we feel it is important to share them so that people are aware of the potential benefits of CPC containing mouthwashes alongside other preventative measures.” ​

Unilever said eminent scientists had reviewed the research data and agreed it was “in the public interest to share the results widely”. ​

‘Further laboratory and clinical assessment’ now needed​

Unilever's findings had been published on the preprint platform for biology research bioRxiv​ where the study researchers said: “Mouthwash containing 0.07% Cetylpyridinium Chloride exhibited virucidal effects providing a ​≥3.0 log reduction HCoV-229E viral count.”​

When comparing ethanol-based mouthwashes, they said: “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.”​

The researchers concluded: “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.”​

Commenting on the findings, Roberts said: “The results of the study are a promising step on our journey to understanding how mouthwashes could help reduce the spread of [SARS-CoV-2], alongside other preventative measures.” ​

Professor Iain Chapple, head of research for the Institute of Clinical Sciences at the UK’s University of Birmingham, agreed and said the results “warrant further exploration with ​in-vitro and human clinical studies"​ that would be important to understand the how long the anti-viral effect lasted. 

Unilever to upscale availability of CPC-based products, kickstart clinical trials in 2021​

Despite the early-stage nature of these findings, Unilever said it was committed to making CPC-based products “available in as many countries as possible”, ​excluding North America, over the coming months.

Speaking to CosmeticsDesign-Europe, Unilever also confirmed it had started “a long-term and robust programme of research” ​that built on this initial preliminary study. The company was working with “experts in the field”,​ it said, to refine what it hoped would include: testing on human saliva; the duration of the effects; and testing various other mouthwash formulations for their effect.

Unilever said it hoped to carry out clinical studies starting next year.