SARS-CoV-2 can be transmitted even from asymptomatic individuals in a variety of ways, including droplets, aerosols and, to a lesser extent, fomites.
Now Brazilian researchers have evaluated the use of these products in a toothbrush disinfection protocol, they report in an article published online in The Journal of Infectious Diseases.
As emphasized by the authors in the text, published as a letter to the editor, individuals infected with SARS-CoV-2 have “high viral loads in saliva, nasopharynx and oropharynx,” which can occur even in asymptomatic humans.
Since toothbrushes can act as reservoirs for microorganisms and promote the transmission of diseases such as COVID-19, the authors estimate that disinfecting the brushes would be important to control the transmission of the virus in shared spaces.
A recent study has shown that commercially available mouthwashes can inactivate SARS-CoV-2 in vitro. The results showed that antiseptic solutions containing ethanol and essential oils – illustrated by the brand Listerine Cool Mint, just to name one – had satisfactory effects in reducing viral load.
However, there are still no specific studies evaluating the effectiveness of different mouthwash solutions in toothbrush disinfection, nor randomized studies showing that the use of such solutions in clinical practice would play a protective role against the transmission of COVID-19.
Disinfection protocol
As suggested by the authors after reviewing the available data on the subject, toothbrush disinfection should follow the following steps:
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Wash your hands with soap and water or clean them with 70% alcohol
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Disinfect the surface of the toothbrush handle with 70% alcohol for 1 minute
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brush your teeth
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Wash the brush and re-disinfect the handle surface with 70% alcohol for 1 minute
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Leave the brush head immersed in a solution containing ethanol and essential oils for 20 minutes
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Store the brush separately after allowing it to dry
According to the authors, the steps for disinfecting the toothbrush with 70% alcohol are important when brushing in collective settings, such as schools or the workplace, and do not need to be performed in the household environment if not desired.
Another important note from the authors: Brushes used by persons known to be positive for SARS-CoV-2 should be discarded immediately after use. The in vitro studies evaluated for the elaboration of the protocol showed that it was possible to observe a satisfactory reduction in viral load with as little as 30 seconds exposure to the tested solution. However, it is important to consider that due to its design, the toothbrush has remanent niches of microorganisms – hence the recommendation for immersion for a longer time.
Need more studies
“Toothbrushes play an essential role in oral hygiene, but they can also act as reservoirs for microorganisms, promoting the transmission of disease in healthy and diseased individuals,” the authors write.
Although the in vitro the efficacy of the ethanol and essential oil solution – as well as that of alternative solutions such as povidone-iodine – has been demonstrated in more than one study, more research is still needed.
“[R]Randomized clinical trials are needed to verify the effectiveness of the oral rinse in preventing the spread of the virus, including evaluation of toothbrush disinfection, “the authors conclude.
The authors have not disclosed any relevant financial relationships.
J Infect Dis. Published online December 28, 2020. Full text
This article originally appeared in the Portuguese edition of Medscape.
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