PRS25 Budget IMPACT Analysis of the CELL-Based Quadrivalent Influenza Vaccine in the German Population Using a Dynamic Transmission MODEL Approach

Abstract

Cell-based influenza vaccine production can avoid egg-adaptation in vaccine viruses, particularly the H3N2 strain, enabling closer match between vaccine antigens and anticipated circulating strains. A closer match to circulating virus strains potentially increases effectiveness of cell-based influenza vaccine. The study aimed to evaluate the budget impact of a national immunization program based on the progressive use of cell-based quadrivalent influenza vaccine (QIVc) versus the current scenario of vaccinating exclusively with standard egg-based quadrivalent influenza vaccines (QIVe) in Germany (aged 9yrs+). The individual-based dynamic transmission model (4Flu) with German demography and contact structure was used to provide realistic estimates of the impact of QIVc over QIVe on age-specific influenza infections. The model was calibrated on German influenza attack rate using national vaccination rates, and combined with a decision tree structure. Relative vaccine effectiveness of QIVc over QIVe was assumed from a US retrospective cohort study. Egg-adapted mismatch was assumed to occur each year, although more conservative scenarios were assessed. Influenza-related probabilities of outpatient visit, hospitalization, mortality, and direct and indirect costs were extracted from published literature. The budget impact model includes a moderate increasing penetration of QIVc over the next 3 years in the German market. Over the 3-year period, switching gradually from QIVe to QIVc produces slightly higher vaccination costs of about €4.1M (+0.2%). The total savings derived from fewer influenza events and complications resulted in significant net budget savings of €131.1M (0.4%) from a societal perspective. Budget savings were mainly driven by the avoidance of complication costs (€14.1M, 0.5%); non-complicated symptomatic cases (€117.5M, 0.4%) and premature death costs (€3.6M, 0.3%). Considering the assumption of egg-adaptation related mismatch occurring 55% of the years, the net budget savings will be €61.3M. Based on the epidemiological and economic models, the introduction of QIVc would be economically favorable in the German immunization program.