Immune imprinting refers to how the immune system's first encounter with a virus, such as influenza, leaves a lasting imprint that shapes future immune responses.1,2 However, influenza vaccines may affect this process—particularly when egg-based ones are used. Tune in to learn about the impact of immune imprinting, the role that vaccines play in this process, and how switching to non-egg-based vaccines could help redirect immune responses and possibly create more effective defenses in people of all ages.3,4

References:

1. King SM, Bryan SP, Hilchey SP, Wang J, Zand MS. First impressions matter: Immune imprinting and antibody cross-reactivity in influenza and SARS-CoV-2. Pathogens. 2023;12(2):169. doi:10.3390/pathogens12020169
2. Zhang A, Stacey HD, Mullarkey CE, Miller MS. Original antigenic sin: How first exposure shapes lifelong anti-influenza virus immune responses. J Immunol. 2019;202(2):335–340. doi:10.4049/jimmunol.1801149
3. Rockman S, Laurie K, Ong C, et al. Cell-based manufacturing technology increases antigenic match of influenza vaccine and results in improved effectiveness. Vaccines (Basel). 2022;11(1):52. doi:10.3390/vaccines11010052
4. Liu F, Gross FL, Jefferson SN, et al. Age-specific effects of vaccine egg adaptation and immune priming on A(H3N2) antibody responses following influenza vaccination. J Clin Invest. 2021;131(8):e146138. doi:10.1172/JCI146138

USA-CRP-24-0038 July 2025