# Explain how vaccination protects individuals from disease by stimulating the immune system.

> IB DP Biology Standard Level (2023 syllabus) — C3.2 Defence against disease · Explain · 4 marks

## Mark scheme (4 marks)

1. A vaccine contains antigens (or weakened/killed pathogens or attenuated pathogen components) that do not cause disease
2. The antigens trigger an immune response, including activation of lymphocytes (B cells and/or T cells) and production of antibodies
3. Memory cells (B memory cells and/or T memory cells) are produced and persist in the body after the initial immune response
4. Upon subsequent exposure to the same pathogen, memory cells enable a faster and stronger secondary immune response, preventing or reducing the severity of disease

## Key terms

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

## Related

- [Revision notes for IB DP Biology Standard Level (2023 syllabus)](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/explain-how-vaccination-protects-individuals-from-bc358bde) · Published by Druglandscape Ltd.