Question
Explain how vaccination protects an individual from a disease such as measles, and discuss why high vaccination rates in a population are important. [6 marks]
Mark scheme — Level-marked:
Level 3 (5–6): Coherent explanation linking vaccine content (dead/weakened/inactivated pathogen or its antigens) → antigen recognition by lymphocytes → production of specific antibodies → formation of memory cells → faster, larger secondary response on re-infection. Includes herd immunity: protects vulnerable individuals (immunocompromised, infants) by reducing transmission; cites threshold (~95% for measles).
Level 2 (3–4): Describes vaccine action and antibody production but limited detail on memory cells OR herd immunity.
Level 1 (1–2): Basic statement that vaccines prevent disease; little mechanistic detail.
0: No relevant content.
6 marks · take your time before peeking.
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Generated by TopMyGrade AI · cross-check official sources before relying on the mark-scheme phrasing.