CAIE A Level Biology 9700 · Immunity
A patient receives a vaccine containing inactivated viral particles. Several years later, the patient is exposed to the live, wild-type virus but does not develop any symptoms. Explain why the secondary immune response is faster and more effective than the primary response, with reference to the roles of specific immune cells and the concept of memory.
5 marks, so the mark scheme is looking for about 5 separate creditworthy points. Making the same point twice in different words earns it once.
Explain means: Give the reasons or the mechanism: why or how something happens. Link each point to the next with because, so or which means. A list of facts with no links usually loses the reasoning marks.
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