Trump and his non-medical friends do not understand the changed definition of vaccine, and are basing their thoughts on a false premise, WHICH HAS BEEN SOLD TO THEM.
Trump would be best served by saying the words, “I don’t know the answer to that, I’m still looking into it.”
Actually that is a false premise.
However, vaccines can become less and less effective as a virus changes. I wouldn’t take last year’s flu vaccine this year, for example...and even that can be a guess as to which strains will be the most dominant year to year.
Very true.