Monday 9 November
Could a cheap iodine mouthwash help beat COVID?
The Times speculates on whether iodine mouthwash might provide some protection against coronavirus. It includes extensive commentary from ‘one of the world’s leading authorities on infection in the mouth and nose, Stephen Challacombe, professor of oral medicine at King’s College London, with a specialism in the immunology of the mucous membranes. His decades of experience meant that when the pandemic hit, his mind went immediately to one - literal solution. Iodine mouthwash. “Yes. I have no doubt that this should be used,” Challacombe says, “and had it been, it would have saved lives.” The article highlights that when the pandemic struck, Professor Challacombe and his colleagues wrote to the British Dental Journal reminding the scientific world of its potential. There followed a flurry of studies showing the effectiveness of iodine mouthwash on COVID-19 in test tubes. They repeatedly concluded that after 15 seconds in contact with a weak solution of this kind of iodine 99.99 per cent of the virus was killed. There soon followed several tests on humans with COVID-19, but in numbers too small to draw conclusions. They indicated that iodine mouthwash pretty much wiped out the COVID-19 for a time. What is needed is larger studies, especially into how long iodine keeps COVID-19 at bay. Sceptics say that the effect could last just a few useless minutes, and point to a mixed bag of results for iodine mouthwash against viruses such as colds. Given this ‘mouthwash is safe, cheap and easy,’ the Times asks ‘should we be using it before we have robust evidence that it kills the virus in humans? “This story becomes in a way a test case of how to balance risk and responsibility.
On the one hand the government’s scientific advisers and the British Dental Association’s verdict is a conservative and cautious no. This mouthwash is well tolerated, but there may be unforeseen risks and little gain. As Ian Jones, a virology professor at the University of Reading, told the Times journalist that the mouthwash may kill the virus, but it may be back in no time; it’s “the constant replacement of the virus that is the issue”. When asked to comment the BDA also considered the Trump factor in championing ‘unproven treatments for COVID-19, such as hydroxychloroquine,’ which in larger trials was found to be ineffective against the virus. The Times also pointed out that ‘in August the governor of Osaka in Japan looked at the limited but encouraging human studies of iodine mouthwash on COVID-19 and told the public: “It’s worth giving a try.” Japan already has an established culture of using iodine mouthwash against common infections, but within hours there was panic-buying across the country, leaving the shelves bare. The Osaka governor’s comments got a slap from the World Health Organisation Centre for Health Development, which responded: “There’s no scientific evidence that gargling medicine prevents the coronavirus.”
Professor Challacombe says that the priority are healthcare workers, especially those working with a lot of saliva, such as anaesthetists and dentists. The American Dental Association, and equivalent bodies in Australia and South Africa, have recommended that dentists ask their patients to mouthwash with iodine or chlorhexidine before procedures. The British Dental Association has refused to follow suit; Professor Damien Walmsley, its scientific adviser, says it is waiting to see results of larger trials.