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Microbiology · Vaccines
Sample itemWhy are booster doses used for some vaccines?
Original practice item, not a recalled exam question. Nothing here is recorded.
The answer and the reasoning
D. Restore or strengthen waning immune protection
Booster doses reinforce immune memory or raise antibody levels when protection declines or exposure risk remains significant over time.
Option by option
A. Replace all public-health surveillance
Surveillance remains important.
B. Eliminate need for cold chain
Cold chain still matters.
C. Cause primary infection intentionally
Vaccines do not intentionally cause disease.
D. Restore or strengthen waning immune protection (correct)
Correct: boosters sustain protective immunity.
Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.