Like I've stated before, I don't believe ANY shots that have to be retweaked and re-administered at the least every year are vaccines.
You've said that.
But it raises questions.
Heck, I don't like that my immune system requires any updates but hey, at least most of them are every ten years or so.
Complexity results from different diseases evolving
at different rates, & by vaccines designed to function
differently.
It sounds like you believe vaccines should all be
"one & done", or they're not a "vaccine". Many
useful vaccines aren't that way, eg, chicken pox.
I highly recommend reading on the history of
vaccines, how they're developed, how they
function, & their varying efficacy.
It's not a simple thing that one can understand
based solely on one's own reaction after each
vaccination.