There’s more to it of course
Since novel strains (the kind that tend to kill people) almost always come from Southeast Asia each year, the lack of travel, especially anyone who is sick with the flu, is a possible major factor in the flu vanishing
Flu strains that most people have immunity to don’t spread
It’s the strains that are new that cause the damage
But in any case, anyone sick with the flu just couldn’t travel in the last year
Ever had it before? Well you got it again.