Question:
"Why Do They Want to Vaccinate Children?"
To demonstrate that The Party has control, Comrades.
To the young children, that their bodies are under control of the government (and The Party). That the government will "take care of them".
To the parents, that it is The Party that will ultimately control what happens to their children, and how they will be raised (via the "educational process").
Hmmm... I see that Comrades Rusty and Skeeter have it exactly right.
But both Comrades must learn the difference between recognizing the truth, and controlling the reality...