Clin Infect Dis. 2023 Jun 30:ciad400. doi: 10.1093/cid/ciad400. Online ahead of print.
BACKGROUND: The effects of Nirmatrelvir/Ritonavir (NMV-r or Paxlovid) on Covid-19 outcomes in younger vaccinated adults are unclear.
OBJECTIVE: To assess if NMV-r use in vaccinated adults aged ≤50 is associated with improved outcomes and identify beneficial and non-beneficial subgroups.
DESIGN/SETTING: Cohort study, TriNetX database.
PARTICIPANTS: We generated two propensity-matched cohorts of 2,547 patients from an 86,119-person cohort assembled from the TriNetX database. Patients in one cohort received NMV-r, and patients in the matched control cohort did not.
MEASUREMENTS: Main outcome: composite of all-cause emergency department visits, hospitalization, and mortality.
RESULTS: The composite outcome was detected in 4.9% of the NMV-r cohort and 7.0% of the non-NMV-r cohort (OR 0.683, CI 0.540-0.864; p=0.001), indicating a 30% relative risk reduction. The number needed to treat (NNT) for the primary outcome was 47. Subgroup analyses found significant associations for patients with cancer (NNT=45), cardiovascular disease (NNT=30), and both conditions (NNT=16). No benefit was found for patients with only chronic lower respiratory disorders (asthma/COPD) or without serious comorbidities. 32% of NMV-r prescriptions in the overall database were for 18-50-year-olds.
CONCLUSION: NMV-r use in vaccinated adults aged 18-50, especially with serious comorbidities, was associated with reduced all-cause hospital visits, hospitalization, and mortality in the first 30 days of Covid-19 illness. However, NMR-r in patients without significant comorbidities or with only asthma/COPD had no association of benefit. Therefore, identifying high-risk patients should be a priority and avoid over-prescription should be avoided.