Why does the initial dose of a tetanus toxoid vaccine not confer long-lasting immunity, requiring booster shots to establish sustained protection?

💡 Explanation

Long-lasting immunity requires high-affinity antibodies produced by plasma cells derived from memory B cells, because the initial immune response stimulates limited affinity maturation. Therefore, booster shots enhance affinity maturation over time, generating high-affinity antibodies, rather than relying on the initial low-affinity response.

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