Meyers' team treated solutions containing a strain of human coronavirus — a readily available and genetically similar alternative for SARS-CoV-2 — with the baby shampoo solutions, various peroxide antiseptic rinses and various brands of mouthwash.
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, the press release stated, so the research team hypothesizes that a similar amount of SARS-CoV-2 may be inactivated upon exposure to the solution.
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.
The 1% baby shampoo solution, often used by head and neck doctors to rinse the sinuses, inactivated more than 99.9% of human coronavirus after two minutes of contact. Several of the mouthwash and gargle products also were effective. Many inactivated more than 99.9% of the virus after only 30 seconds of contact, and some inactivated 99.99% of the virus after 30 seconds.
Meyers said the next step is to design and conduct clinical trials to evaluate whether products like mouthwashes can effectively reduce viral load in COVID-19 positive patients.
“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 and leader of the research team. “Certain professions including dentists and other health care workers are at a constant risk of exposure. Clinical trials are needed to determine if these products can reduce the amount of virus COVID-positive patients or those with high-risk occupations may spread while talking, coughing or sneezing. Even if the use of these solutions could reduce transmission by 50%, it would have a major impact.”
The study was published in the Journal of Medical Virology.