Number of hydroxychloroquine prescriptions per month for patients with coronavirus disease 2019 (COVID‐19) in Japan from January 2020 to November 2021. The blue bars show the monthly number of chloroquine prescriptions for COVID‐19 among patients in the Medical Data Vision database, which includes data on approximately 20% of acute care hospitals in Japan. The gray line shows the national number of COVID‐19 notifications in Japan by month over the same period.