The spanish flu killed way more than that, at least according to wikipedia. Something like 10-20%. It was a monumental event that killed a percentage of the entire global population. The kind of thing you can only call a true plague. Think like the black plague, where a substantial percentage of some populations where wiped off the face of the earn. Imagine 1/3 or 1/2 of your community dying.

I keep seeing this 2.5% number, and I don't understand what people are talking about.