# Vaccination programmes aim to protect large populations from infectious diseases. Explain why a person who has been vaccinated against a disease is protected if they are later exposed to the live pathogen.

> WJEC GCSE Biology (Wales) — 2.6.2 The immune system · Explain · 4 marks

## Mark scheme (4 marks)

1. The vaccine contains antigens (from the pathogen) which are recognised as foreign
2. White blood cells produce antibodies specific to those antigens
3. Memory cells are produced / remain in the body after the initial immune response
4. On exposure to the live pathogen, memory cells allow a faster/larger antibody response so the person does not become ill

## Key terms

- [vaccination](https://www.gradenine.co.uk/glossary/vaccination)

## Related

- [Revision notes for WJEC GCSE Biology (Wales)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/vaccination-programmes-aim-to-protect-large-98f2be73) · Published by Druglandscape Ltd.