Publication date: Sep 01, 2025
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. 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. 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. 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.
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| Concepts | Keywords |
|---|---|
| Covid | COVID-19 |
| Outpatient | effectiveness |
| Taiwan | nirmatrelvir–ritonavir |
| Vaccination | severe outcomes |
| Taiwan |
Semantics
| Type | Source | Name |
|---|---|---|
| drug | DRUGBANK | Ritonavir |
| disease | MESH | COVID-19 |
| disease | MESH | death |
| disease | MESH | Infectious Diseases |
| pathway | REACTOME | Reproduction |
| disease | MESH | morbidity |
| drug | DRUGBANK | Etoperidone |
| disease | IDO | symptom |
| drug | DRUGBANK | Methionine |
| drug | DRUGBANK | Oxygen |
| disease | IDO | process |
| disease | MESH | privacy |
| disease | IDO | country |