One can't prove a negative.
It's beyond any kind logic or reason to assume the vaccine killed a 99-year old, who could die at any moment because of her age.
Your paranoia is embarrassment to both conservatives and Christians. But, it's choice you're making. But, I'll be damned if it hurts conservatives politically.
I am trying to summon up my Philosophy Logic Courses from a very long ago. I seem to recall that a Tautological Proof began with the assumption of a negative, then steps were taken in order to methodically prove the ‘negative.’
If the negative could be unproved, then the Proof was determined to be a positive. It the ‘positive’ could not be proved in that fashion then the negative was then ‘proved.’ I know that I no longer have those text books but I may still have my notes.