Kobayashi Pharmaceutical's Iodine Research Wins 'Thesis Award' from Japan's Society for Antibacterial and Antifungal Agents, Inactivating Over 99.9% of SARS-CoV-2 in 15 Seconds

Kobayashi Pharmaceutical Co., Ltd. has received the 'Thesis Award' at the 54th General Meeting of the Society for Antibacterial and Antifungal Agents, Japan (May 29, 2026, in Osaka) for its research on 'The Inactivating Effect of Iodine on SARS-CoV-2 and the Virus Inactivation and Germicidal Effects of Oral and Pharyngeal Medicines.' This award is given to the most outstanding paper published in the society's journal over the past year.

Key Research Findings - Research on the virus-inactivating effect of 'iodine' won the 'Thesis Award' at the 54th General Meeting of the Society for Antibacterial and Antifungal Agents, Japan. - An iodine aqueous solution inactivated over 99.9% of viruses such as SARS-CoV-2 and influenza within 15 seconds of application. - The methodology, which visually demonstrated the antiviral effect of iodine using time-lapse video and electron microscopy, was highly evaluated.

<Background of the Award-Winning Research> In recent years, following the influenza epidemic and the spread of COVID-19, society as a whole has demanded more reliable infection control measures. While the effectiveness of disinfectant ingredients like iodine against certain viruses was known, the inactivating effect in a shorter time frame relevant to actual use, and the difference in effectiveness compared to other ingredients at the same concentration, had not been fully verified. To address this, the company conducted in vitro experiments in collaboration with a third-party testing organization.

<Research Content> 1. Various Viruses Inactivated by 99.9% or More with 15 Seconds of Iodine Action A 0.5w/w% iodine aqueous solution was applied to various viruses, including SARS-CoV-2 and influenza A, for 15 seconds, confirming an inactivation effect (loss of infectivity) of over 99.9%. A comparative evaluation was also conducted with other disinfectant/anti-inflammatory ingredients used in commercial oral and pharyngeal medicines (Cetylpyridinium Chloride Hydrate: CPC, Sodium Azulene Sulfonate: Azulene), indicating that iodine may have a superior virus-inactivating effect under the same concentration and time conditions.

2. Successful Visualisation of Virus Inactivation After applying a 0.5w/w% iodine aqueous solution to SARS-CoV-2 for 15 seconds, the state of host cells upon inoculation was observed with time-lapse video. While cells without iodine treatment showed progressive degeneration and destruction, cells treated with iodine were observed to maintain a state similar to before infection. Furthermore, scanning electron microscopy of these cells showed no virus particles, and the ciliary structure on the cell surface was maintained without destruction. Additionally, transmission electron microscopy of influenza A virus treated with the iodine solution confirmed denaturation of the virus's envelope.

<Future Outlook> Kobayashi Pharmaceutical has been conducting basic research on disinfectant ingredients like iodine for some time. The company believes this research, as knowledge of its effectiveness against viruses, will contribute to infectious disease control research and be of service to society.