Even a third less is probably still plenty. And the putative immune system benefit strikes me as hypothetical unless the exposure and effect are quantified.
Well, I've got all mine, unless another booster is available that I don't know about. One thing about vaccines is that you know exactly who got them, and who didn't. This probably makes it a lot easier to study.
And I'm willing to believe that some childhood exposure to pathogens is beneficial, but I don't think we know how much of a good thing is enough, or too much.
Do you think that we’ve discovered and cataloged the sum total of milder pathogens that protect against worse illnesses in a lab? Got all mine means “got all the ones we currently know enough about to develop a vaccine for.”
