Passive immunity is only acquired once in your life, at birth and during breastfeeding. Active immunity is called active because your body reacts to something. Ex. you inhale an allergen, your body reacts, therefore you get active immunity to it. Getting an immunization introduces a dead virus to your body, your body still reacts to it, therefore it is called active immunity.
good luck xx
I would cite my Immunology textbooks, but they don't do you much good on here!
· 1 decade ago