And there’s a non-zero chance that it lives dormant in your brain and you die several years later. Absolutely bonkers.

And by "it" you mean measles? Or do you mean the vaccine? Completely reverses the message of your post!

What is the evolutionary advantage of this? I mean, if the host dies subsequently that's pretty bad for both parties, or?

Wait, measles erases antibody memory?

First of all, this is scary. Secondly, I wonder if it hase the same effect on autoimmune disease?