Cosmetic mouthwashes help manage bad breath but do not really kill the bacteria that cause bad breath.
It has been suggested that SARS-CoV-2, the causative agent of COVID-19, replicates in the throat, meaning the throat area has a high viral load. As a result, the person can spread the virus more readily while speaking, coughing or breathing.
A lot of people had initially believed that mouthwashes could kill the coronavirus and stop the spread of the disease. This was busted as a myth by the World Health Organisation; they stated that neither swishing nor gargling with mouthwash could kill SARS-CoV-2.
In May, a group of researchers claimed that mouthwashes may neutralise the coronavirus by damaging its lipid coat just like soaps and alcohol.
It has previously been indicated that antiseptic mouthwashes can reduce viral load in the oral cavity of SARS and MERS patients.
Now, a study done at the Ruhr-University Bochum, Germany suggests that mouthwashes may not kill the virus but would be able to reduce viral load in the throat thus reducing the chances of transmission.
The study is published in the Journal of Infectious Diseases, a peer-reviewed journal by the Infectious Disease Society of America.
Mouthwashes against COVID-19 infection
Mouthwashes are oral care products that act as an adjunct to the daily oral hygiene measures such as brushing and flossing. There are two types of mouthwashes — cosmetic and therapeutic.
Cosmetic mouthwashes help manage bad breath but do not really kill the bacteria that cause bad breath. They are available over-the-counter.
Therapeutic mouthwashes, on the other hand, contain active ingredients like chlorhexidine, peroxide, fluoride, and essential oils. These kill pathogenic bacteria and help control oral conditions like plaques, tooth decay, and bad breath.
“Therapeutic mouthwashes tend to have antibacterial and anti-microbial properties which help them kill all the microorganisms, both good and bad, present in the oral cavity. However, there has been no research on whether these mouthwashes can deactivate or kill viruses, including SARS-CoV-2 virus,” said Dr Sonia Bhatt, a dental surgeon associated with MyUpchar.
The latest finding
In the latest research, scientists studied the effects of eight different oral rinses available in Germany against SARS-CoV-2 under conditions mimicking the nasopharyngeal mucosa. The viral particles were mixed with various mouthwashes and a substance that mimics saliva and the suspension was mixed for 30 seconds to mimic gargling. As a control, the culture medium was used in a few mixtures in place of mouthwashes. Culture mediums are preparations that are used to grow microbes in the lab. All the mixtures were then cultured to note if any viral growth occurs.
Interestingly, viral load was found reduced in all the test mixtures (ones with the mouthwash) and some even had almost no virus after 30 seconds. The medium did not affect the infectivity of the virus suggesting that the effect was indeed due to mouthwash and not due to the saliva mimicking solution.
The study suggested that while mouthwashes or gargling cannot keep the virus from multiplying inside the cells, it may be able to reduce the viral load in the oral cavity and throat for a while, which may, in turn, reduce the transmission of the disease to an extent.
Researchers at the Ruhr-University Bochum are now planning to do clinical studies to assess whether the same effects are seen in patients and for long do the effects last. Clinical trials for the same have already been registered by the University of California San Francisco and the University of Karachi.
For more information on the transmission of COVID-19, read our article on How does COVID-19 spread.
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