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Scientists around the world have been working tirelessly to find ways to decrease and eliminate the spread of the novel coronavirus. Recently, several studies were published regarding the efficacy of nasal and oral rinses to kill or inactivate the COVID-19 virus.
Multiple studies have confirmed that certain mouthwashes do have the potential to inactivate the COVID-19 virus in your mouth with 30 or more seconds of contact. However, these findings do not confirm that mouthwash can help reduce the transmission of COVID-19 throughout the population. Additionally, mouthwash and nasal rinses are not effective treatments for the virus.
More research will need to be done in order to confirm the virucidal properties of mouthwashes and whether they can be useful in stopping the spread of COVID-19.
In July, The Journal of Infectious Diseases published a study from a team of scientists in Germany that showed how commercially available mouthwashes affected the viral load of three different strains of Covid. All of the mouthwashes were effective at reducing the viral load, however, only three mouthwashes were able to reduce viral infectivity by up to three orders of magnitude to background levels. These were:
In September, researchers from Pennsylvania State University College of Medicine published an article in the Journal of Medical Virology detailing the results of their experiments with nasal and oral rinses. Their research showed similar results.
Three Oral rinses with hydrogen peroxide (H2O2) as the active ingredient were able to reduce the infectious virus by 90% to 99%. These mouthwashes included:
Crest Pro-Health (active ingredient: cetylpyridinium chloride [0.07%]) was more effective, decreasing infectious virus rates by 99.9% or 99.99%.
Listerine Antiseptic (active ingredients: Eucalyptol [0.092%], Menthol [0.042%], Methyl salicylate [0.060%], Thymol [0.064%]) was the most effective oral rinse in this trial, decreasing the infectious virus levels greater than 99.99%.
A third study by Cardiff University published their preliminary findings in November which also aligned with the other studies. They stated that:
“During a 30 second exposure, two rinses containing cetylpyridinium chloride and a third with ethanol/ethyl lauroyl arginate eliminated live virus to EN14476 standards (>4-log10 reduction), while others with ethanol/essential oils and povidone-iodine (PVP-I) eliminated virus by 2-3-log10. Chlorhexidine or ethanol alone had little or no ability to inactivate virus in this assay.”— Brief Report: The Virucidal Efficacy of Oral Rinse Components Against SARS-CoV-2 In Vitro
Prior to the Covid-19 Pandemic, nasal sprays and irrigation were used as an effective way to decrease bacterial and viral loads from the sinus cavities. Now scientists are actively studying if nasal rinses can help combat the viral load and transmission of Covid.
The study at Pennsylvania State University College of Medicine also examined the effect of nasal rinses to inactivate the virus. They noted that over-the-counter saline nasal rinse (Neti Pot) had no effect on the virus, while 1% baby shampoo solution was able to inactivate more than 99% of the virus after one minute of contact time and over 99.9% after two minutes of contact time.
Some early studies are showing that a povidone-iodine nasal spray may be effective in killing the virus in as little as 15 seconds. While it is early in usage, some hospitals are using method as an appropriate treatment to protect busy areas like hospital waiting rooms and clinics.
These results show that there is virucidal potential in both oral and nasal rinses. More research is needed to confirm the virucidal abilities of mouthwashes. More research will also be necessary to determine if mouthwash or nasal rinses have any potential to help reduce the spread of COVID-19.
You should not use mouthwash as a replacement for other methods of risk reduction.
Mouthwash is not a cure for COVID-19.
Certain mouthwashes may have the potential to add another measure of risk reduction, especially in dental settings where aerosol production is high.
However, you should continue to wear a mask, social distance, and wash your hands frequently in order to help stop the spread of the COVID-19 virus.
Meister, Toni Luise, et al. “Virucidal Efficacy of Different Oral Rinses Against Severe Acute Respiratory Syndrome Coronavirus 2.” The Journal of Infectious Diseases, vol. 222, no. 8, 29 July 2020, pp. 1289–1292., doi:10.1093/infdis/jiaa471.
Meyers, Craig, et al. “Lowering the Transmission and Spread of Human Coronavirus.” Journal of Medical Virology, 17 Sept. 2020, doi:10.1002/jmv.26514.
Statkute, Evelina, et al. “Brief Report: The Virucidal Efficacy of Oral Rinse Components Against SARS-CoV-2 In Vitro.” 13 Nov. 2020, doi:10.1101/2020.11.13.381079.