A vaccine is just a dumbed down version of the virus, so getting one is just like catching the virus just with little to no symptoms. (Unless you have a bad immune system.)
Actually we remember it because a bunch of stupid people died defending a cannon that wasn’t theirs to demonstrate that they were independent from a land that rightfully owned that place. But mexico was sort of not exactly all that good back then, so those folks weren’t wrong, they were just stupid.
We have seen him clean a few times before. (Not for long though.)