If you can access the full article then you can find your generational immunity based on what flu version went around when you were a kid Excerpt https://www.science.org/doi/10.1126/science.aag1322 Lifelong protection against severe influenza The first influenza attack that a child suffers can affect the way that their lifelong immunity to the virus builds up. A wide range of influenza A virus subtypes infect humans. Subtype H5 belongs to HA group 1 (which also includes H1 and H2 subtypes), and subtype H7 belongs to HA group 2 (which also includes the H3 subtype). Gostic et al. found that birth-year cohorts that experienced first infections with seasonal H3 subtype viruses were less susceptible to the potentially fatal avian influenza H7N9 virus (see the Perspective by Viboud and Epstein). Conversely, **older individuals who were exposed to H1 or H2 subtype viruses as youngsters were less susceptible to avian H5N1-bearing viruses.** A mathematical model of the protective effect of this imprinting could potentially prove useful to predict the age distribution and severity of future pandemics.