Abstract
BackgroundMutations of the H3N2 vaccine strain during the egg-based vaccine manufacturing process seem to partly explain the suboptimal effectiveness of traditional seasonal influenza vaccine. Cell-based influenza vaccines avoid such egg-adaptation, thereby improving antigenic match and vaccine effectiveness. The objective of this study was to evaluate the public health and economic impact of a cell-based quadrivalent influenza vaccine (QIVc) in adult population (18–64 years) compared to the standard egg-based quadrivalent influenza vaccine (QIVe), in the US.MethodsThe impact of QIVc over QIVe in terms of public health and costs outcomes was estimated using a dynamic SEIR transmission model. The model is age-structured and accounts for 4 circulating influenza strains (A/H1N1pdm9, A/H3N2, B(Victoria), and B(Yamagata)). It was calibrated on US attack rate and strain circulation for the seasons 2013–2018. US specific absolute vaccine effectiveness for QIVe, specific hospitalization rate, mortality rate, Quality-Adjusted Life Years (QALYs) and costs were extracted from published literature. Relative vaccine effectiveness of QIVc over QIVe for subjects 18–64 years of age was obtained from a US retrospective cohort study. Robustness of the results was assessed in univariate and probabilistic sensitivity analyses.ResultsSwitching from QIVe to QIVc in the 18–64 year-old population may prevent 5.7 M symptomatic cases, 1.8 M outpatient visits; 50K hospitalizations and 5,453 deaths annually. The switch could save 128 K QALYs and US$ 845M in direct costs, resulting in a cost-saving alternative in a 3-year time horizon analysis. Probabilistic sensitivity analyses confirmed the robustness of the cost-saving result.ConclusionsThe analysis shows that QIVc is expected to prevent a substantial number of hospitalizations and deaths, and would result in substantial savings in health care costs.
Determination of the potency of a cell-based seasonal quadrivalent influenza vaccine using a purified primary liquid standard
