Were you not paying attention as the vaccines were initially released? Healthcare workers had priority access first. Then higher age groups + healthcare workers had access. Then various lesser aged groups and/or medical conditions + higher age+healthcare workers had access. And then finally kids were included.
The data seems to have changed a bit, because as we gained more and more knowledge about covid, we were able to start tweaking our approach.
We didn't know at first, how it was spread. Some viruses, such as polio, are spread through consumption and gi tract. I, and many others, were initially hosing canned groceries down with bleach solutions, and thoroughly washing all fruits and veggies. In addition to social distancing and wearing masks.
Then, as we learned more about the virus, we felt that social distancing and wearing masks was more important, and hosing down groceries was less important. Because we learned this was a respiratory virus spread via respiration and breath, not through consumption.
Feel free to correct me if I'm wrong.