Private
Same thing. Survivors tended to have some natural immunity, and there have been a lot of advances since those days. The virus mutates fairly rapidly, which is why it hasn't been completely eliminated, but the flu is only a real problem in my time in areas with poor health care and sanitation. Unfortunately, the poor will always be with us, no matter how hard we try to make things better.
Ran into the same sort of things quite a few times when I did various internships for my Care of Magical Creatures studies. Worth taking a quick look and listen at any rate. No guarantees, of course, but it sounds like something that was covered during my refresher in Vienna.