Describe how vaccination protects a person from becoming ill when they are exposed to a pathogen.

Eduqas GCSE Biology — 2.6.2 The immune system · Describe · 4 marks · View as Markdown

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

Model answer (4 marks)

The vaccine contains a dead, weakened or harmless form of the pathogen (or its antigens). White blood cells recognise these antigens and produce antibodies. Memory cells are also created, so the immune system remembers the pathogen. When the person is later exposed to the real pathogen, the memory cells trigger a rapid, large‑scale antibody response that destroys the pathogen before illness develops.

Examiner tips

Use the exact terms: vaccine, antigens, antibodies, memory cells, rapid response
Show the sequence: vaccine → antibody production → memory cells → faster response on exposure
Mention that the pathogen is destroyed before symptoms appear

Common mistakes

Confusing the vaccine with the live pathogen itself
Failing to mention memory cells or the speed/quantity of the antibody response
Using vague language such as "immune system" without specifying antibodies or memory cells

Mark scheme (4 marks)

The vaccine contains a dead, weakened or harmless form of the pathogen (or its antigens)
White blood cells produce antibodies in response to the antigens in the vaccine
Memory cells are produced so the immune system 'remembers' the pathogen
On future exposure to the pathogen, antibodies are produced more quickly / in greater quantity so the pathogen is destroyed before the person becomes ill

Key terms in this question

vaccination