Claim: The 1918 flu (a subtype of H1N1 from 1918–20), Asian flu (a subtype of H2N2 rom 1957–58), and Hong Kong flu (a subtype of H3N2 from 1968–69) are the only known major modern influenza pandemics.
Evidence: Major modern influenza pandemics 1889–90 flu pandemic 1918 flu Asian flu Hong Kong flu 2009 flu pandemic Typical seasonal flu