Vaccinating most of the people in a population reduces the number of new cases of a disease in people who have not been vaccinated. Which explains why?
Vaccinated people do not become infected, so cannot pass the pathogen on
Vaccinated people produce toxins that kill the pathogen in other people
Vaccinated people pass their protection to others by direct contact
Vaccinated people remove the pathogen from the air that others breathe
176 exam-style questions on AQA GCSE Biology 3.1 Communicable diseases, covering 3.1.1 Communicable (infectious) diseases, 3.1.2 Viral diseases, 3.1.3 Bacterial diseases, 3.1.4 Fungal diseases, 3.1.5 Protist diseases, 3.1.6 Human defence systems, 3.1.7 Vaccination, 3.1.8 Antibiotics and painkillers, and 3.1.9 Discovery and development of drugs. Each one has a worked solution and a mark scheme showing where the marks go.