You are the nurse in a pediatrician’s office. You are taking vital signs of a child who was in the hospital for pertussis last month. The child is unvaccinated. The mother asks, “Now that he has had pertussis, is he immune to it?” The best response from the nurse would be:

Choice A reason: Passive, natural immunity involves antibody transfer (e.g., via breast milk) and is temporary, not resulting from infection. Pertussis infection induces active immunity through the body’s immune response, producing memory cells, making this an incorrect description of the immunity gained from natural infection. Choice B reason: Passive, artificial immunity occurs through antibody administration (e.g., immunoglobulin injections), not natural infection. Pertussis infection triggers the body’s immune system to produce antibodies and memory cells, conferring active immunity, making this an incorrect choice for the immunity acquired after recovering from pertussis. Choice C reason: Active, natural immunity develops after recovering from an infection like pertussis, where the immune system produces antibodies and memory cells specific to Bordetella pertussis. This provides long-term protection against reinfection, accurately describing the immunity the unvaccinated child gained, making this the correct response. Choice D reason: Active, artificial immunity results from vaccination, not natural infection. Pertussis infection induces active, natural immunity through the body’s immune response, not an artificial stimulus like a vaccine, making this an incorrect description of the immunity acquired by the child after recovering from the disease.