Nirmatrelvir/ritonavir (Paxlovid) reduces hospitalization, mortality in patients 65+ with COVID-19; effect on younger patients unclear

Reference

Arbel R, Wolff Sagy Y, Hoshen M, et al. Nirmatrelvir use and severe Covid-19 outcomes during the omicron surge. N Engl J Med 2022;387(9):790-798.

Synopsis

The primary study used to approve nirmatrelvir/ritonavir (Paxlovid) for use in outpatients with COVID-19 only included high-risk, unvaccinated patients. This study from a large health system in Israel identified adults 40 years and older who were eligible to receive the drug during the omicron surge. They compared patients who did and did not receive Paxlovid within 5 days of a confirmed diagnosis of COVID-19. Overall, 78% of included patients had previous immunity by vaccination, prior infection, or both. The analysis was adjusted for comorbidities, demographics, ethnicity/religious affiliation, and socioeconomic status. Approximately 80% of participants were considered fully vaccinated. Data were stratified by age, and a benefit was only seen for persons 65 years and older. In that group, the rate of hospitalization was lower (14.7 vs 58.9 cases/100,000 person-days; adjusted hazard ratio [HR] 0.27; 95% CI 0.15 - 0.49) and the risk of death (HR 0.21; 0.05 - 0.82). There was no difference for either outcome in patients aged 40 to 64 years. Previous research has shown a higher overall risk for patients older than 50 years, but results for 50- to 64-year-old patients were not reported in this study. A second study from a preprint server from Hong Kong compared outcomes in outpatients given Paxlovid with those who were untreated. That study found lower rates of mortality (HR = 0.25; 0.13 - 0.47) and lower rates of hospitalization (HR = 0.69; 0.60 - 0.79) in patients given Paxlovid. That study found no difference in benefit by age, although only approximately 20% of the patients in the study were younger than 65 years and only 35% were fully vaccinated.