Inhaled Zanamivir vs Oral Oseltamivir to Prevent Influenza-related Hospitalization or Death: A Nationwide Population-based Quasi-experimental Study.

BACKGROUND

Meta-analyses of individual patient data from randomized, controlled trials show that early oseltamivir treatment for influenza cut the risk of pneumonia and hospitalization by 44% and 63%, respectively. However, data on the effectiveness of inhaled zanamivir in preventing hospitalization and death are lacking.

METHODS

This nationwide, population-based, cohort study included all outpatients treated with inhaled zanamivir or oral oseltamivir within 48 hours after a clinical diagnosis of influenza before and after the rollout of inhaled zanamivir as the first-line antiviral in Taiwan. The main outcome was influenza-related hospitalization or death within 14 days. Those who developed the outcome within 2 days were excluded from analyses. Propensity score stratification was used to control confounding from covariates.

RESULTS

A total of 865 032 eligible influenza outpatients were included in the analysis. The risk of developing the main outcome (adjusted hazard ratio [aHR], 1.01; 95% confidence interval [CI], .96 to 1.06) did not differ between the inhaled zanamivir group (n = 595 897, 68.9%, the reference) and the oral oseltamivir group (n = 269 135, 31.1%). Prespecified analysis on high-risk subgroups further showed that inhaled zanamivir is not inferior to oral oseltamivir in either patients aged ≥65 years (aHR, 1.14; 95% CI: 1.05 to 1.25) or patients with chronic lung diseases (aHR, 1.23; 95% CI: 1.08 to 1.41).

CONCLUSIONS

Inhaled zanamivir is not inferior to oral oseltamivir as outpatient treatment in preventing influenza-related hospitalization or death for patients whose conditions do not require hospitalization within 2 days.

Informations de copyright

© The Author(s) 2022. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: [e-mail].

Déclaration de conflit d'intérêts

Potential conflicts of interest. C.-T. F. reports support for the present work from the Taiwan National Health Insurance Agency (NHI Claims Database). K. A. C. reports research grants to the National Taiwan University Hospital outside of the submitted work from Takeda, MSD, Amgen, and Boehringer Ingelheim; consulting fees paid to self from Bayer, Analysis Group, and Atheneum; and writing support for a manuscript from Novartis. The remaining authors: No reported conflicts of interest. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed.