Certain oral antiseptics and mouthwashes may offer a way to inactivate human coronavirus, according to a new study.
The findings indicate that some of these products might help reduce the viral load, or amount of virus, in the mouth after infection and may help reduce the spread of SARS-CoV-2, the coronavirus that causes COVID-19.
The researchers found that several of the nasal and oral rinses had a strong ability to neutralize human coronavirus, which suggests that these products may have the potential to reduce the amount of virus spread by people who are COVID-19-positive.
“The products we tested are readily available and often already part of people’s daily routines,” said Craig Meyers, professor of microbiology and immunology and obstetrics and gynecology at Penn State.
Meyers and colleagues used a test to replicate the interaction of the virus in the nasal and oral cavities—major points of entry and transmission for human coronaviruses—in the rinses and mouthwashes.
They allowed the solutions to interact with the virus for 30 seconds, one minute, and two minutes, before diluting the solutions to prevent further virus inactivation. The outer envelopes of the human coronavirus tested and SARS-CoV-2 are genetically similar, Meyers said, so the research team hypothesizes that exposure to the solution may inactivate a similar amount of SARS-CoV-2.
To measure how much virus was inactivated, the researchers placed the diluted solutions in contact with cultured human cells. They counted how many cells remained alive after a few days of exposure to the viral solution and used that number to calculate the amount of human coronavirus that was inactivated as a result of exposure to the mouthwash or oral rinse that was tested.
The 1 percent baby shampoo solution, often used by head and neck doctors to rinse the sinuses, inactivated greater than 99.9 percent of human coronavirus after a two-minute contact time.
Several of the mouthwash and gargle products also were effective at inactivating the infectious virus. Many inactivated greater than 99.9 percent of the virus after only 30 seconds of contact time and some inactivated 99.99 percent of the virus after 30 seconds.
The results with mouthwashes are promising and add to the findings of a study showing that certain types of oral rinses could inactivate SARS-CoV-2 in similar experimental conditions, Meyers said.
“People who test positive for COVID-19 and return home to quarantine may possibly transmit the virus to those they live with,” said Meyers, a researcher at Penn State Cancer Institute.
Future studies may include a continued investigation of products that inactive human coronaviruses and what specific ingredients in the solutions tested inactivate the virus.