Molnupiravir and nirmatrelvir-ritonavir remain efficacious for unvaccinated COVID-19 patients with chronic respiratory diseases in real-world settings

16 Nov 2023


Novel antiviral options such as molnupiravir (MOV) and nirmatrelvir-ritonavir (NMV-r) are designed to be viable and effective treatments for mild to moderate Coronavirus disease 2019 (COVID-19) infections.1 However, there is still a considerable knowledge gap in the efficacy of these medications among unvaccinated individuals who suffer from chronic respiratory diseases.1 To address this gap, researchers from the University of Hong Kong (HKU) commenced a population-cohort study to assess the efficacy of MOV and NMV-r respectively in the management of COVID-19 outcomes of this patient subgroup.1

This was a retrospective, territory-wide cohort study conducted in Hong Kong, which enrolled 3,267 COVID-19 adult patients who were unvaccinated and had comorbid chronic respiratory diseases, including asthma, chronic obstructive pulmonary disease (COPD) and bronchiectasis.1 Among the recruited patients, 17.7% and 9.2% of patients received MOV and NMV-r respectively, while the rest of the study population received no antiviral treatment.1 The primary outcome of this study was the incidence of COVID-related outcomes in each patient cohort, which included hospitalization, respiratory failure, severe respiratory failure, and mortality.1


Primary endpoint:
  • The primary endpoint was the reported COVID-19-related outcomes of each cohort, consisting of hospitalization, respiratory failure, severe respiratory failure, and mortality1
  • Compared with the no-treatment cohort, the NMR-v cohort had a significant 66.6% (aRR=0.334; 95% CI: 0.26-0.85; p=0.007) risk-reduction in COVID-19-related respiratory failure and a 77.0% (aRR=0.23; 95% CI: 0.07-0.94%; p=0.039) risk-reduction in severe respiratory failure with borderline statistical significance was reported in COVID-19-related hospitalization (p=0.057) and in-hospital mortality (p=0.051)1
  • Significantly lower incidences of COVID-19-related severe respiratory failure and in-hospital mortality were observed in the MOV cohort when compared to the no-treatment cohort, resulting in a 48.2% (aRR=0.52; 95% CI: 0.005-0.73; p=0.048) and 58.3% (aRR=0.42; 95% CI: 0.23-0.77; p=0.005) risk-reduction for the two respective outcomes1


"In summary, both nirmatrelvir-ritonavir and molnupiravir  are effective for reducing severe outcomes in unvaccinated  COVID-19 patients with chronic respiratory diseases"

Dr. Kwok, Wang-Chun
Department of Medicine,
The University of Hong Kong,
Hong Kong

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