 The study compares the projected health and economic outcomes of using quadrivalent iiv4 versus trivalent iiv3 influenza vaccines in the U.S. with a cost-effectiveness model interacting with a dynamic transmission model that tracks vaccination cases interactions and recovery over 10 years. The results show that iiv4 reduces annual influenza cases by 1,973,849 discounted 2,325,644 undiscounted resulting in 12 to 13 percent fewer cases and complications and deaths and translates into 18,485 more quality adjusted life years annually. The study predicts that iiv4 is cost-saving with direct medical savings of 0.1 billion annually 5.6 percent after accounting for indirect costs. This article was offered by Anita J. Brogan, Sandra E. Talbird, Ashley E. Davis and others.