My priors would go the opposite way: a full-body checkup cannot clear out the plaque in my arteries, lower my blood pressure, strength my vascular walls, and there's no miracle drugs that definitively address those. I think of a checkup that says "good to go, won't die in the next year!" is more like an auto checkup, where we do diagnostics then can take definitive action, it's more a warning of what's to come.

That being said saying odds are one of them dies before the election is uncomfortably high doesn't compute, at all, ex. the best steelman I can come up with is its supposed to translate to "P(Trump dies | Biden Dies) >= 50%", which I very much doubt is true if you look at actuarial tables.