Changes in Prescribing Patterns of Antiviral Drugs before and after Public Coverage Termination among Hospitalized COVID-19 Patients in Regional Hospitals in Japan: A Retrospective, Multicenter Study

In Japan, antiviral agents for COVID-19 were freely available until September 2023 as part of national policy. This study evaluated changes in these agents’ prescribing patterns and the patient outcomes following the policy shift. We conducted a multicenter retrospective study at four hospitals in Japan’s Okayama and Kagawa prefectures from January 2022 to March 2024. The study period was divided into the public-expenditure phase (January 2022 to September 2023) and the post-expenditure phase (October 2023 to March 2024). We extracted the hospitalized patients’ clinical data from the electronic database. The study’s primary outcome was the antiviral prescription rate; the secondary outcome was in-hospital mortality. Among the 302 hospitalized patients (median age 85 years), 52.0% were classified as having a mild condition. Of the patients with mild conditions, 37.7% were diagnosed in outpatient settings prior to hospitalization. During the public-expenditure phase, 47.4% of the patients received antivirals as outpatients, mainly molnupiravir (80.9%). In the post-expenditure period, 80.0% of the patients were prescribed antivirals, mostly molnupiravir (91.7%). The antiviral prescription rate was significantly higher after the policy change. The overall in-hospital mortality was 15.8%, with no significant difference between the two periods (17.0% vs. 10.5%). Despite the termination of government funding, antiviral prescriptions remained frequent at community hospitals located in highly aging regions of western Japan such as Okayama and Kagawa prefectures. Mortality remains high among the elderly, highlighting the need for continued antiviral therapy and booster vaccinations.