What would the immunization schedule for an adult never exposed to germs be like?

Suppose we have an adult in their late 20s who was never exposed to people and their germs, but now will be since they’ll be living among the rest of us. Obviously said person would need to be immunized for the same diseases we all are starting at birth since they’d be coming in contact with disease for the first time.

Would they be immunized on the same slow schedule that infants are, or quicker?

Basically I’m unsure if vaccinations are typically done over the first couple of years because babies are small or because their immune systems are immature. If it’s more the former, that wouldn’t be a problem with our hypothetical adult, but if it’s mostly the latter, his/her immune system would be just as immature. Right?

And speaking of their immune system being like a child’s…(weaned) babies and toddlers get sick all the time. Part of this is because they don’t have immunity to sickness since they’re encountering it for the first time, but they’re also kind of icky the way they touch everything and put dirty things in their mouths and make each other sick at daycare. If our person was taught proper hygiene upon their arrival, would they be sick all of the time still? How much of not getting our coworker’s illnesses is proper hand washing, and how much is that we’ve likely been exposed to their bugs before?

My best friend had a form of leukemia, for which the treatment was to totally wipe out her immune system, give her a bone marrow transplant, and wait for her immune system to build up again before releasing her from a quarantined hospital room, which seems close enough to your hypothetical. She was given the series of vaccinations in the same manner as infants (and would send out happy emails/texts listing her booster shot/immune system “age”)

I’m not sure about your last question, other than to say that my friend’s immune system is considerably weaker than most people’s, and despite being a nurse in a cancer ward (yes, she is that awesome) which requires her to hand wash and wear protective clothing most of the time, and doing everything she can to protect herself, she still gets colds/sick very often. New strains of the cold and flu are pretty much guaranteed to get her. It sucks, but hey, she’s alive!