Abstract
While molnupiravir (MOV) and nirmatrelvir-ritonavir (NMV-r) were developed for treatment of mild to moderate COVID-19 infection, there has been a lack of data on the efficacy among unvaccinated adult patients with chronic respiratory diseases, including asthma, chronic obstructive pulmonary disease (COPD) and bronchiectasis. A territory-wide retrospective cohort study was conducted in Hong Kong to investigate the efficacy of MOV and NMV-r against severe outcomes of COVID-19 in unvaccinated adult patients with chronic respiratory diseases. A total of 3267 patients were included. NMV-r was effective in preventing respiratory failure (66.6%; 95% CI, 25.6-85.0%, p = 0.007), severe respiratory failure (77.0%; 95% CI, 6.9-94.3%, p = 0.039) with statistical significance, and COVID-19 related hospitalization (43.9%; 95% CI, -1.7-69.0%, p = 0.057) and in-hospital mortality (62.7%; 95% CI, -0.6-86.2, p = 0.051) with borderline statistical significance. MOV was effective in preventing COVID-19 related severe respiratory failure (48.2%; 95% CI 0.5-73.0, p = 0.048) and in-hospital mortality (58.3%; 95% CI 22.9-77.4, p = 0.005) but not hospitalization (p = 0.16) and respiratory failure (p = 0.10). In summary, both NMV-r and MOV are effective for reducing severe outcomes in unvaccinated COVID-19 patients with chronic respiratory diseases.