^
"A minor issue if I’m likely to die of other causes long before that could get me, but a bigger concern if it has more time to develop. "
Time. Your dependent variable.
Independent variable: Getting the shot or not.
If you don't get the shot, you may contract the disease next week and die soon or five years hence.,
If you do get the shot, you won't die immediately but may die from the cancer (or whatever) you are only hypothesizing five years from now.
The "five years" is a arbitrary number you can take to mean any long term period. Fear, whether reasoned or unreasoned, is another independent variable in this analysis, but not addressed herein.
Decision: Get the shot.
If anyone posts a Spock image at this point, Ah swayuh Ah'l come and gitcha.
Terry, 230RN