1.2.3  Summary of types of specific immunity

Table 1.1 gives a summary of the four different types of specific immunity, with examples to illustrate each of them.

Table 1.1  Summary of different types of specific immunity.
Type of specific immunityExample of how immunity might be acquired
Naturally acquired immunityActiveInfection
PassiveMaternal antibodies crossing the placenta, or in breastmilk
Artificially acquired immunityActiveIntentional exposure to antigens in a vaccine
PassiveInjection or transfusion of someone else’s antibodies

  • You give a polio vaccination containing polio antigens to a baby girl. What type of immunity will the child develop? Explain your answer.

  • The child will develop artificially acquired active immunity. She was deliberately exposed to polio antigens in the vaccine, so her immunity is artificially acquired. She produced her own antibodies and memory cells directed against the polio antigens, so her immunity is active.

1.2.2  Artificially acquired immunity

1.2.4  Herd immunity