Nirmatrelvir-ritonavir use among adults hospitalized with COVID-19 during the Omicron phase of the COVID-19 pandemic, Canadian Nosocomial Infection Surveillance Program.

Background

Recent studies have demonstrated the effectiveness of nirmatrelvir-ritonavir in reducing the risk of progression to severe disease among outpatients with mild to moderate coronavirus disease 2019 (COVID-19); however, data are limited regarding the use and role of nirmatrelvir-ritonavir among hospitalized patients. This study describes the use and outcomes of nirmatrelvir-ritonavir among adults hospitalized with COVID-19 in a sentinel network of Canadian acute care hospitals during the Omicron variant phase of the pandemic.

Methods

The Canadian Nosocomial Infection Surveillance Program conducts surveillance of hospitalized patients with COVID-19 in acute care hospitals across Canada. Demographic, clinical, treatment and 30-day outcome data were collected by chart review by trained infection control professionals using standardized questionnaires.

Results

From January 1 to December 31, 2022, 13% (n=490/3,731) of adult patients (18 years of age and older) hospitalized with COVID-19 in 40 acute care hospitals received nirmatrelvir-ritonavir either at admission or during hospitalization. Most inpatients who received nirmatrelvir-ritonavir, 79% of whom were fully vaccinated, had at least one pre-existing comorbidity (97%) and were of advanced age (median=79 years). Few were admitted to an intensive care unit (2.3%) and among the 490 nirmatrelvir-ritonavir treated inpatients, there were 13 (2.7%) deaths attributable to COVID-19.

Conclusion

These findings from a large sentinel network of Canadian acute-care hospitals suggest that nirmatrelvir-ritonavir is being used to treat adult COVID-19 patients at admission who are at risk of progression to severe disease or those who acquired COVID-19 in hospital. Additional research on the efficacy and indications for nirmatrelvir-ritonavir use in hospitalized patients is warranted to inform future policies and guidelines.

Déclaration de conflit d'intérêts

Competing interests A McGeer reported receiving research grants to the Sinai Health System from the COVID-19 Immunity Task Force, the Canadian Institutes of Health Research, Merck, Pfizer and Sanofi Pasteur; and receiving personal fees from AstraZeneca, GlaxoSmithKline, Janssen, Medicago, Merck, Moderna, Novavax, Pfizer and Sanofi Pasteur outside the submitted work. J Conly reported receiving research grants and funding from the Canadian Institutes for Health Research. He has participated in World Health Organization-funded studies outside of the submitted work. He was the primary local investigator for a study funded by Pfizer for which all funding was provided to the University of Calgary. Outside of the submitted work, he has received travel support from the Centers for Disease Control and Prevention and bioMérieux Canada. Outside of the submitted work, he is involved in multiple World Health Organization groups for which no funding is received. No other disclosures were reported.