Could mouthwash really protect you against coronavirus?

Mouthwash is able to kill coronavirus within 30 seconds of exposure to it in a laboratory, a new scientific study has found.

Earlier this year, a team of scientists from Cardiff University called for urgent research to be conducted into whether mouthwash could be effective in reducing the spread of coronavirus.

At the time, researchers highlighted the importance of the throat and saliva glands in the replication of Covid-19 and said they believed mouthwash had the potential to destroy the outermost layer or ‘envelope’ of the virus, thus preventing it from replicating in the mouth and throat in the early stages of an infection.

Now, the same team of scientists has shared the preliminary findings of a new study that shows “promising signs” of mouthwashes capable of doing this.  

So, what did the study show and should we be using mouthwash to ward off Covid-19? Here is everything you need to know.

The research, which was conducted at Cardiff University, found that mouthwashes containing 0.07 per cent of the ingredient cetylpyridinium chloride (CPC) showed "promising signs" of reducing Covid-19.

Scientists carried out tests at the university's laboratory by mimicking the conditions of a person's naso/oropharynx passage and using mouthwash brands including Dentyl.

Their report, titled The Virucidal Efficacy of Oral Rinse Components Against SARS-CoV-2 In Vitro, is yet to be peer reviewed but supports a separate study that was published last week which found CPC-based mouthwashes are effective in reducing Covid's viral load.  

Dentyl is the only UK mouthwash brand to have taken part in the 12-week clinical trial, which was led by Professor David Thomas.

In February, the World Health Organisation (WHO) responded to claims that gargling mouthwash could protect you from infection, stating: “There is no evidence that using mouthwash will protect you from infection with the new coronavirus. Some brands of mouthwash can eliminate certain microbes for a few minutes in the saliva in your mouth.

"However, this does not mean they protect you from 2019-nCoV infection."

The researchers from Cardiff University’s School of Medicine claim that mouthwash may be able to damage the coronavirus membrane and reduce infection rates.

A clinical trial will next examine how effective over-the-counter mouthwash is in reducing the levels of Covid-19 in the saliva of coronavirus patients at the University Hospital of Wales in Cardiff. The results are expected to be published in early 2021.  

Dr Thomas told the PA news agency: "Although this in-vitro study is very encouraging and is a positive step, more clinical research is now clearly needed. 

"We need to understand if the effect of over-the-counter mouthwashes on the Covid-19 virus achieved in the laboratory can be reproduced in patients, and we look forward to completing our clinical trial in early 2021."  

Dr Nick Claydon, a specialist periodontologist, said he believed the research was "very valuable".  

He added: "If these positive results are reflected in Cardiff University's clinical trial, CPC-based mouthwashes such as Dentyl used in the in-vitro study could become an important addition to people's routine, together with hand washing, physical distancing and wearing masks, both now and in the future." 

The government has issued advice on how best to protect yourself from Covid-19.

This includes staying at home as much as possible, working from home if you can, limiting contact with other people, staying 2m away from other people if you go out and washing your hands regularly.

The guidelines also advise people to wear a facial covering when in enclosed spaces such as using public transport or shopping.

NHS advice on avoiding spreading Covid-19 includes covering your mouth and nose with a tissue or your sleeve (not your hands) when you cough or sneeze, as well as washing your hands often for at least 20 seconds when you arrive home after being out.

Anyone with a high temperature or a new, continuous cough is also being asked to stay at home for seven days, and avoid going to GP surgeries, pharmacies and hospitals.