In a town, most people are vaccinated against a disease spread by contact between people. A small number of people cannot be vaccinated.
Why does high vaccination coverage help protect these people?
More vaccinated hosts release antibodies, so immunity passes through contact between different people.
Fewer susceptible hosts remove antigens, so the pathogen can no longer cause disease.
More vaccinated hosts release antibiotics, so pathogens entering unvaccinated people are rapidly destroyed.
Fewer susceptible hosts reduce transmission, so exposure to the pathogen becomes less likely.
45 exam-style questions on Edexcel GCSE Biology 5.3 Immune system and medicines, covering 5.3.1 The specific immune system, 5.3.2 Response to immunisation, 5.3.3 Advantages and disadvantages of immunisation, 5.3.4 Antibiotics and bacterial infections, 5.3.5 Aseptic techniques in culturing, 5.3.6 Cross-sectional areas of cultures, 5.3.7 Stages of developing new medicines, and 5.3.8 Production of monoclonal antibodies. Each one has a worked solution and a mark scheme showing where the marks go.