Real‐World Use of Kampo Medicine for Persistent Pain After COVID ‐19 Vaccination: A Retrospective Observational Study

Aim To describe the real‐world use of Kampo medicine in patients with persistent pain after COVID‐19 vaccination and to summarize their clinical courses. Methods We conducted a single‐center retrospective observational study at a university hospital in Japan. Patients with persistent pain lasting for ≥ 4 weeks after COVID‐19 vaccination were included. Clinical data were extracted from electronic medical records. Patients were classified into Kampo and non‐Kampo groups depending on whether Kampo medicine was prescribed during follow‐up. Kampo prescriptions were individualized based on traditional pattern‐oriented assessments, including pain characteristics, constitutional features, and associated symptoms. Pain improvement and time to pain improvement were assessed descriptively based on clinical documentation. Results Fifteen patients were included, of whom seven received Kampo treatment and eight did not. Kampo prescriptions were individualized based on traditional assessments and were modified during follow‐up according to symptom evolution and clinical judgment. Documented pain improvement was observed in 8 of 15 patients, with a median time to improvement of 28.5 days (IQR 24.5–75.3). Conclusion This retrospective observational study describes real‐world Kampo medicine practice for persistent pain after COVID‐19 vaccination, including individualized prescription patterns and modifications during follow‐up. Further prospective studies are needed to better characterize the role of Kampo medicine in this condition.