104. Association of Oseltamivir use with Clinical Outcomes of Children Hospitalized with Influenza — Influenza Hospitalization Surveillance Network, 2014-2023

Abstract Background Antiviral treatment has been shown to lower risk of intensive care unit (ICU) admission in children with influenza, though data are limited. National U.S. guidelines recommend antiviral treatment for all hospitalized patients with influenza; however, use has declined since 2019-20, particularly in pediatrics. Our objective was to assess the association between oseltamivir receipt and clinical outcomes among pediatric influenza-associated hospitalizations.Figure 1.Flow Chart of children with laboratory-confirmed influenza hospitalizations within FluSurv-NETTable 1:Patient Characteristics, Overall and Stratified by Oseltamivir Receipt and Timing for ICU analysis Methods This retrospective cohort study used data from FluSurv-NET, which conducts population-based seasonal surveillance for laboratory-confirmed influenza hospitalizations for all ages across 13 US states. Surveillance staff completed chart abstractions using a standard case report form. We included children < 18 years old hospitalized with influenza during 2014/2015-2022/2023. Adjusted Cox proportional hazard models with oseltamivir receipt as a time-dependent exposure were used to estimate the hazard of intensive care unit (ICU) admission and hospital length of stay (LOS) (see table 2 and 3 for time variable definitions). Covariates for model adjustment were selected from univariate Cox regression analysis (p< 0.2) or a priori.Table 2:Adjusted Cox Models of Oseltamivir Receipt on Hazard of Intensive Care Unit (ICU) Admission Multivariate model with adjusted hazard ratios and p-values for ICU outcome (time from symptom onset to ICU admission with patients censored at discharge). Covariates selected from univariate Cox regression analysis with hazard ratio p-value