How privilege works?

I was shocked recently when I found out that someone I know who is older than me, more educated than I am, and has successfully raised multiple children to adolescence didn't know how vaccines work. I'm not talking anything complicated, just the basic fact that it introduces a small, controlled amount of the virus in question so your immune system learns to recognize that and knows how to fight it. (I know that it's more complicated than that and they don't always use the actual virus in question, but you see what I'm saying in general terms, as a very rudimentary description of the concept.)

This shocked me because I learned how vaccines work when I was a kid, probably around the age of 4. My mother explained it to me (in a simplified, child-appropriate way like my explanation above) so I would understand why I had to get a needle.

I was so surprised that a proper grownup didn't know this basic fact of life that I got talking with my mother about it.

Mom: "Well, not everyone has as much education..."
Me: "I didn't learn this from education, I learned it from you when I was like 4. Where did you learn it from?"
Mom: **thinks** "I learned it from my father when I was a kid and had to get a needle."
Me: "And where did Grandpa learn it from?"
Mom: **thinks** "He must have learned it in university."

So because my grandfather studied various science in university like 65 years ago, this piece of knowledge has, in our family, gone from being higher scientific education to conventional wisdom passed on from parent to child, like nursery rhymes and bible stories and household hints. It doesn't feel like privilege, it doesn't feel like rarefied scientific knowledge, it doesn't feel like a concept that you have to go to university to learn. It's just something your mommy tells you when you're a kid, like how to braid your hair.

My maternal grandfather has 16 direct descendants - 4 children and 12 grandchildren - and all of us have known how vaccines work since childhood. Any children we might have or might ever be responsible for will also know how vaccines work since childhood. Even if none of us had ever pursued higher education, we'd all still be in possession of this information that originally comes from higher education, whereas our peers who don't have an ancestor who learned about vaccines in university don't have this information before it comes up in school

I also find myself wondering how this relates to Lareau's concept of entitlement. Simply by growing up in a household where my parents could explain the reasons behind necessary medical procedures, I get the idea that I'm allowed to know the reasons behind any medical procedures I might be ordered to undergo. I'd totally ask for an explanation if ever instructed to undergo a medical procedure I don't understand, and I wouldn't even feel like I'm exercising entitlement in doing that. But perhaps if you grew up getting a needle because you have to, because they won't let you go to school if you don't, perhaps limited to the explanation "It's so you don't get the flu," you might be accustomed to undergoing medical procedures you don't fully understand, and it might never even occur to you to ask for an explanation. Then when you have to take your children to the doctor, it's totally "Because I said so" or "Listen to the doctor, he's a doctor."