I thought we'd get 3 vaccinations and be free until the year is up?

I thought we'd get 3 vaccinations and be free until the year is up ? The pediatrician comes today and says in 6 months to take a blood test ??‍♀️ Have you taken one? Why? ? I don't trust our pediatricians, they've been there for a hundred years and here suddenly a guest appears and on your forehead without explanations, asks "Do you need it?"