ABSTRACT
BACKGROUND: The pandemic of coronavirus disease 2019 (COVID-19) has caused heavy burdens on national healthcare systems. Nirmatrelvir-ritonavir (Paxlovid) may be one of the most promising therapeutic drugs, with reports of up to 89% reduction rates in hospitalization risk and death among patients with mild-to-moderate COVID-19 who are at risk of developing severe disease. However, limited studies have investigated the effects of this class of drugs on viral clearance and length of hospital stay. METHODS: In this study, we retrospectively analyzed the characteristics of patients infected with the Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and investigated the effects of oral nirmatrelvir-ritonavir on viral clearance and length of hospital stay in mild-to-moderate COVID-19 patients at high risk for progression to severe disease. RESULTS: The median SARS-CoV-2 negative conversion time was 16 (13-20) versus 13 (10-16) days (control group versus nirmatrelvir-ritonavir group, p < 0.001), the median length of hospital stay was 13 (10-16) versus 12 (13-14) days (control group versus nirmatrelvir-ritonavir group, p = 0.01), and the SARS-CoV-2 negative conversion time and length of hospital stay were significantly shorter in the nirmatrelvir-ritonavir group than in the control group. When controlling for hypertension, chronic kidney disease, severity status of COVID-19, use of antibiotic agent, and COVID-19 vaccine received, multiple stepwise linear regression analysis showed that nirmatrelvir-ritonavir treatment was negatively associated with the SARS-CoV-2 negative conversion time and length of hospital stay. CONCLUSION: Nirmatrelvir-ritonavir reduces the viral clearance time and length of hospital stay in hospitalized patients with COVID-19. Nirmatrelvir-ritonavir might be a promising drug to reduce the virus load and the heavy burden of healthcare systems.