Originally Posted by JGordon

:eh: No, many flu strains have been around for decades. The 1918 flu strain (Spanish Flu) that killed 20+ million people is still around in significant numbers today.

If you are referring to the minor RNA changes in each individual flu viruses compared to its progenitor virus, influenza viruses are not considered to be new "strains" unless they have functional differences in virulence, structure, or some other factors.