Kampo Medicine for Prolonged COVID-19 Symptoms: An Observational Study (2026)
Hachinohe, Japan – A prospective observational study conducted at Hachinohe City Hospital has revealed potential insights into managing prolonged symptoms following COVID-19, often referred to as “long COVID” or Post-Acute Sequelae of COVID-19 (PASC). The study, involving 114 patients experiencing persistent symptoms, investigated the efficacy of a treatment regimen incorporating traditional Japanese Kampo medicine tailored to individual patient profiles.
Researchers, led by Tsuyoshi Kawamura of the Department of Field Medicine at Hachinohe City Hospital, analyzed data collected between May 2022 and December 2023. The study focused on tracking changes in patient performance status (PS, ranging from 0-9) and the severity of 16 specific symptoms, assessed using a numerical rating scale (NRS) from 0 to 10. The findings suggest a correlation between initial fatigue levels and the time required to achieve a PS score of 2 or less, indicating improved functional capacity.
Specifically, the study found that patients presenting with higher general fatigue scores at their first visit – those at or above the median – demonstrated a significantly slower rate of improvement in their PS status. The hazard ratio for this group achieving a PS ≤ 2 was 0.405 (95% Confidence Interval: 0.253-0.650, P value not specified in the abstract). This suggests that individuals with more pronounced initial fatigue may require a longer duration of treatment to experience substantial functional gains.
The treatment approach employed in the study centered on individualized Kampo medicine prescriptions, a system of traditional Japanese herbal medicine. Kampo treatments were selected based on a comprehensive assessment of each patient’s specific symptoms and overall condition. Researchers acknowledge that observational studies, while valuable for identifying potential interventions and gathering real-world data, offer weaker empirical evidence than randomized controlled trials due to the potential for confounding biases. As stated in research guides from the Pacific College of Technology, observational studies are limited by the inability to control risk assignment and maintain symmetry of unknown confounders.
The research team included members from multiple institutions, including the Department of Obstetrics and Gynecology at Hachinohe City Hospital, the Department of Education and Support for Regional Medicine at Tohoku University Hospital, and the Department of Kampo and Integrative Medicine at Tohoku University Graduate School of Medicine. Akira Kanda, Ryo Arai, Satoshi Tanaka, and Toshiaki Ito, affiliated with the Department of Kampo and Integrative Medicine at Tohoku University, disclosed a grant received from Tsumura & Co., a company specializing in Kampo medicine. The Tohoku University Benefit Reciprocity Committee reviewed and managed potential conflicts of interest, ensuring adherence to university guidelines. Kawamura and Tanaka also reported receiving payments for lectures from Tsumura & Co.
The study’s findings align with broader observations regarding the prevalence and persistence of symptoms following COVID-19 infection. Recent research, including a study by Iba et al. (2024) in Japan, has documented the ongoing burden of post-COVID-19 condition, particularly during periods dominated by the Omicron BA.5 variant. Globally, estimates suggest a substantial proportion of individuals experience persistent fatigue, cognitive difficulties, and respiratory symptoms after acute COVID-19 infection, as highlighted by Wulf Hanson et al. (2022).
The authors have not indicated any immediate plans for follow-up studies, but the findings contribute to the growing body of evidence exploring potential therapeutic strategies for managing the complex and multifaceted challenges posed by long COVID.