> ”Pretty much every modern influenza variant is a derivative of the Spanish flu”
Not really. While it was true for much of the last century that many “seasonal flu” viruses were direct descendents from H1N1 Spanish flu, the H1N1 that caused the 2009 “swine flu” pandemic was a distinct strain combining new genes of pig, avian, and human flu origins. Since then, derivatives of that virus have replaced earlier ones as the most common circulating H1N1 types.
And right now the most common circulating influenza is actually H3N2 from a completely different (avian) lineage with origins in the 1968 pandemic.
Not really. While it was true for much of the last century that many “seasonal flu” viruses were direct descendents from H1N1 Spanish flu, the H1N1 that caused the 2009 “swine flu” pandemic was a distinct strain combining new genes of pig, avian, and human flu origins. Since then, derivatives of that virus have replaced earlier ones as the most common circulating H1N1 types.
And right now the most common circulating influenza is actually H3N2 from a completely different (avian) lineage with origins in the 1968 pandemic.