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IGCSEBiology
Trial Class

Original practice · 5 questions · 15 marks · about 17 minutes

Vaccination and Herd Immunity Practice Questions

Biology editorial review is supported by the named review panel. Reviewer participation may vary by guide. Checked against Cambridge IGCSE Biology 0610 (2026–2028); last reviewed August 2026.

These questions test your understanding of vaccination, how it produces immunity, and the concept of herd immunity in populations.

Before you open the answers

  • Attempt every question without notes.
  • Show working for calculations and write complete biological statements.
  • Use the suggested time as a guide, not a strict limit on the first attempt.

These are original practice questions. They do not reproduce an official Cambridge paper or official mark scheme.

  1. Question 1

    Paper 4 Both 4 marks Difficulty 3/5

    Explain how vaccination produces immunity to a disease.

    Show model answer and marking guidance
    1. A vaccine contains dead or weakened (attenuated) pathogens, or parts of them (antigens).
    2. The immune system recognises the antigens as foreign.
    3. Lymphocytes produce antibodies and memory cells.
    4. If the live pathogen enters later, memory cells produce antibodies quickly: preventing disease.

  2. Question 2

    Paper 4 Extended 3 marks Difficulty 4/5

    Distinguish between active immunity and passive immunity. Give one example of each.

    Show model answer and marking guidance
    1. Active immunity: the body produces its own antibodies (and memory cells): e.g. Vaccination or natural infection. Long-lasting.
    2. Passive immunity: antibodies are received from another source: e.g. Breast milk or injection of antibodies. Short-lived.
    3. Active involves memory cells; passive does not.

  3. Question 3

    Paper 4 Extended 3 marks Difficulty 3/5

    Define herd immunity and explain why it is important for people who cannot be vaccinated.

    Show model answer and marking guidance
    1. Herd immunity occurs when a large proportion of the population is vaccinated / immune.
    2. The pathogen cannot spread easily because most people are immune.
    3. This protects individuals who cannot be vaccinated (e.g. Very young, immunocompromised): they are less likely to encounter the pathogen.

  4. Question 4

    Paper 2 Core 2 marks Difficulty 2/5

    Explain why a person does not usually get chickenpox twice.

    Show model answer and marking guidance
    1. After the first infection, memory cells are produced by lymphocytes.
    2. If the virus enters again, memory cells rapidly produce antibodies: destroying it before symptoms develop.

  5. Question 5

    Paper 4 Extended 3 marks Difficulty 4/5

    Suggest why a new flu vaccine must be developed each year.

    Show model answer and marking guidance
    1. The influenza virus mutates frequently / rapidly.
    2. New strains have different antigens on their surface.
    3. Antibodies from last year's vaccine may not recognise the new antigens: a new vaccine is needed.

Mark the set consistently

Award a point only when the idea is clearly present in the written answer. Correct any missed point in a complete sentence, then test the same skill on a different question several days later.

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