Booster doses of a vaccine are given in order to
- A. reduce the side effects of the first dose
- B. raise the antibody level and strengthen immunological memory
- C. replace antibodies that have expired
- D. treat an existing infection
Explanation
Each booster re-stimulates memory cells, driving antibody concentration higher and memory longer, the classic secondary response curve. Vaccines prevent rather than treat, so a booster is never therapy.