Osaka Gov. urges use of iodine gargle solution for COVID treatment, but experts wary

OSAKA -- Povidone-iodine gargle solution products have disappeared from store shelves in some parts of Japan after Osaka Gov. Hirofumi Yoshimura announced "research" findings on Aug. 4 that a group of people who gargled with the solution for a few days after testing positive for the new coronavirus later had more negative results from saliva testing than those who didn't gargle.

Meanwhile, experts warn that the incorrect use of such a solution could cause health hazards.

The study was conducted by Osaka Habikino Medical Center run by the Osaka Prefectural Hospital Organization, on the assumption that if the virus in a person's saliva is reduced, it will prevent the symptoms from becoming severe. In its experiment, about 40 people staying at hotels in Osaka Prefecture in June-July recovering from mild symptoms of COVID-19 were divided into two groups: one group that gargled with povidone-iodine solution four times a day for four days and the other that did not gargle at all. As a result, 56.3% of the non-gargling group continued to test positive for the virus, while the figure for those who gargled was 21%.

Dr. Akifumi Matsuyama, director of the next-generation pharmaceutical development center at Osaka Habikino Medical Center who joined Gov. Yoshimura and Osaka Mayor Ichiro Matsui at the Aug. 4 news conference, said, "Gargling might work to reduce the virus in one's saliva," while stating that work still needs to be done to verify its effectiveness in preventing transmission. He also explained that the relation of the virus found in saliva and that in the body remained unclear and required further testing.

Yoshimura began the news conference by saying, "It sounds hard to believe, but it's true. A study found that povidone-iodine solution could be effective in treating corona," while commercially available gargling products were lined up at the conference venue. He then called on those who have common cold-like symptoms such as a fever and their family members, workers at establishments involving food and close-contact customer services, as well as medical and care workers to use the solution when gargling.

Meanwhile, Toshio Takatorige, professor of public health at Kansai University in western Japan, expressed skepticism regarding the use of povidone-iodine solution for the coronavirus. "It might be effective for people who have cold-like symptoms such as coughing, but it could be harmful when people are misled into thinking that it could work for prevention," said Takatorige, raising the alarm on the wide use of the solution even among healthy people.

Povidone-iodine solution needs to be treated with caution when used by pregnant women as well as those with thyroid diseases, and professor Takatorige added, "There is indigenous oral and gastrointestinal flora in a person's body, and the solution could disrupt the balance (of such organisms)." He further expressed concerns over Yoshimura's suggestion of using povidone-iodine, saying, "It could be poisonous when used the wrong way and there are more than a few people who are allergic to it. A recommendation should be made while clearly saying who should use it. I think the governor is being overeager (in recommending that people use it)."

(Japanese original by Hirokage Tabata and Koki Matsumoto, Osaka Science and Environment News Department)