Real-World Effectiveness of Nirmatrelvir-Ritonavir Against Severe Outcomes of COVID-19 in Taiwan: A Nationwide Population-Based Cohort Study.
Journal
Open forum infectious diseases
Journal Volume
12
Journal Issue
9
Start Page
Article number ofaf553
ISSN
2328-8957
Date Issued
2025-09
Author(s)
Abstract
Background Real-world data evaluating the effectiveness of nirmatrelvir–ritonavir across diverse age groups and vaccination statuses remain limited, particularly in East Asian populations. This study evaluates its effectiveness in reducing severe COVID-19 outcomes using a large, comprehensive nationwide healthcare database and to provide new evidence. Method This retrospective observational cohort study involved outpatient COVID-19 patients diagnosed between 1 January 2022, and 1 December 2022, within Taiwan's National Health Insurance Research Database. Patients who received nirmatrelvir–ritonavir were compared with untreated patients. Primary outcomes include COVID-19-related hospitalization, ICU admission, invasive ventilatory support, death, and the composite outcome of hospital admission or death. Results A total of 2 300 131 nonhospitalized patients with confirmed COVID-19 between 1 January 2022 and 1 December 2022, including 530 807 patients treated with nirmatrelvir–ritonavir and 1 769 324 untreated patients. Treatment with nirmatrelvir–ritonavir was associated with a significantly lower risk of COVID-19-related hospitalization (hazard ratio 0.32 [95% CI .31–.34]), ICU admission (0.41 [.38–.45]), invasive ventilatory support (0.38 [.33–.43]), death (0.42 [.40–.45]), and the composite outcome of hospital admission or death (0.34 [.33–.35]). Effectiveness was consistent across subgroups stratified by age and vaccination status, with the greatest benefit observed in unvaccinated individuals and those aged ≥65 years with additional risk factors. Conclusions In a large, nationally representative cohort, outpatient use of nirmatrelvir–ritonavir was associated with a significantly lower risk of severe COVID-19-related outcomes, regardless of age or vaccination status. These findings reinforce the clinical value of early antiviral treatment, particularly in aging and unvaccinated populations.
Subjects
COVID-19
Taiwan
effectiveness
nirmatrelvir–ritonavir
severe outcomes
SDGs
Type
journal article