Real-world Effectiveness of Molnupiravir and Nirmatrelvir/Ritonavir as Treatments for COVID-19 in Patients at High Risk

Background. Using a retrospective cohort study design, we aimed to evaluate the effectiveness of molnupiravir and nirmatrelvir/ritonavir in patients with SARS-CoV-2 who were highly vulnerable. Methods. The impact of each drug was determined via comparisons with age-matched control groups of patients positive for SARS-CoV-2 who did not receive oral antiviral therapy. Results. Administration of molnupiravir significantly reduced the risk of hospitalization (odds ratio [OR], 0.40; P <.001) and death (OR, 0.31; P <.001) among these patients based on data adjusted for age, previous SARS-CoV-2 infection, vaccination status, and time elapsed since the most recent vaccination. The reductions in risk were most profound among elderly patients (=75 years old) and among those with high levels of drug adherence. Administration of nirmatrelvir/ritonavir also resulted in significant reductions in the risk of hospitalization (OR, 0.31; P <.001) and death (OR, 0.28; P <.001). Similar to molnupiravir, the impact of nirmatrelvir/ritonavir was more substantial among elderly patients and in those with high levels of drug adherence. Conclusions. Collectively, these real-world findings suggest that although the risks of hospitalization and death due to COVID19 have been reduced, antivirals can provide additional benefits to members of highly vulnerable patient populations.