Explain why a person who has already had chickenpox is unlikely to become ill from the chickenpox virus again.

Eduqas GCSE Biology — 3.2 Communicable disease · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Chickenpox is a communicable disease caused by a virus. After a person recovers from chickenpox, their immune system retains a 'memory' of the pathogen.

Model answer (4 marks)

The immune system produces antibodies in response to the chickenpox virus (antigen). Memory cells/lymphocytes are produced and remain in the body after the first infection. On re‑exposure to the same pathogen, antibodies are produced more quickly and in greater quantities. The pathogen is destroyed before it can cause illness, so symptoms do not develop.

Examiner tips

  • Use the word ‘antibodies’ and ‘memory cells’ – these are key terms.
  • Show the sequence: infection → antibody production → memory cells → rapid response on re‑exposure.
  • Mention that the rapid response prevents symptoms.
  • Keep the answer concise – 4 marks can be earned with 4 short sentences.

Common mistakes

  • Confusing ‘memory cells’ with ‘memory antibodies’ – both are needed.
  • Failing to state that the response is faster and stronger on re‑exposure.
  • Omitting that the virus is destroyed before symptoms appear.

Mark scheme (4 marks)

  1. The immune system produces antibodies in response to the chickenpox virus (antigen)
  2. Memory cells / lymphocytes are produced and remain in the body after the first infection
  3. On re-exposure to the same pathogen, antibodies are produced more quickly / in greater quantities
  4. The pathogen is destroyed before it can cause illness / symptoms do not develop

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