Gargling with mouthwash that contains the common antiseptic povidone iodine may reduce the number of coronavirus particles in a patient’s nose and throat, research suggests.
Povidone iodine concentrations as low as 0.5% have inactivated the coronavirus in just 15 seconds in laboratory studies.
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| Betadine - Povidone iodine |
To better understand the potential of mouthwashes with this key ingredient, scientists from the University Hospital of Poitiers in France analysed 24 people who had tested positive for the infection in the past 48 hours.
Half the patients – who had coronavirus symptoms but were not severely ill – gargled 25ml of a mouthwash containing 1% povidone iodine four times in a row for five days. They also sprayed 2.5ml of the same solution up each nostril.
After one day, swabs revealed the patients’ viral loads were 75% lower; compared to a 32% reduction among those who did not have the mouthwash treatment.
Although unclear, a reduction in coronavirus particles – known as the viral load – in a patient’s nose and throat may help cut transmission when they sneeze or cough.
Could mouthwash combat coronavirus transmission?
This is not the first time mouthwash has been discussed as a potential coronavirus treatment.
In May 2020, scientists from Cardiff University called for research into whether high-street versions of the dental hygiene product reduces the infection’s transmission.
As well as povidone iodine, mouthwash ingredients like ethanol and cetylpyridinium have been shown to disrupt the fatty membrane of pathogens like the coronavirus.
“In test tube experiments and limited clinical studies, some mouthwashes contain enough of known virucidal ingredients to effectively target lipids in similar viruses,” said Professor Valerie O’Donnell, from Cardiff University.
The coronavirus is known to replicate in the salivary glands and throat, which mouthwashes reach.
It is also said to be “highly sensitive to agents that disrupt lipid bio-membranes”. Other viruses from the same class, which can cause common colds or Severe acute respiratory syndrome (Sars), have been inactivated by “biocidal agents”.
In 2017, a group of scientists found exposing a pathogen from the coronavirus class to 34% ethanol “completely prevented subsequent viral replication”.
When it comes to povidone iodine specifically, Professor Stephen Challacombe from King’s College London previously said: “I have no doubt this should be used and had it been, it would have saved lives.”
Some believe there is nothing to lose, with these mouthwashes being inexpensive, readily available and relatively safe.