I wasn't around when last years zombie outbreak happened, so I am hoping that someone will explain to me how the HA's got progressively "worse" in stages?

I just got the infection today, how/when will the next stage happen?

They are tracking the viruses here. That topic will also tell you about last year :)

thank you!!!

You're welcome~ ^_^

The stages progress automatically based on time; you don't have to do anything to initiate the next stage if that's what you're asking. :) I'd expect to wait at least twelve hours between stages.

.. That's based on last year, anyway. This year might have surprises in store for all we know.