While molnupiravir and nirmatrelvir-ritonavir were developed for treatment of mild to moderate COVID-19 infection, there has been lack of data on the efficacy among unvaccinated adult patients with chronic respiratory diseases, including asthma, COPD and bronchiectasis.

A territory-wide retrospective cohort study on the efficacy of molnupiravir and nirmatrelvir-ritonavir against COVID-19 infection in unvaccinated adult patients with chronic respiratory diseases.

Total 3267 patients were included. Nirmatrelvir-ritonavir 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 probably 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. Molnupiravir 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 with anti-viral effectiveness of and (58.3%; 95% CI, 22.9 ? 77.4, p=0.005).

Nirmatrelvir-ritonavir and molnupiravir are effective in preventing COVID-19 related severe respiratory failure. Nirmatrelvir-ritonavir have extra benefits in preventing COVID-19 related respiratory failure among unvaccinated adult patients with chronic respiratory diseases and probably COVID-19 related hospitalization.