RT @TheodoreLytras
@georgepavlakis @EpiEllie @MackayIM @ArisKatzourakis And as far as the flu is concerned (the original question by @MackayIM), for us epi people things are clear:

Flu is an *endemic* disease that causes seasonal *epidemics* of varying timing, intensity and impact, as well as the occasional flu *pandemic* when it shifts.