Immunity and vaccinationEdexcel A-Level Biology B: Flashcards

Exam questions on Immunity and vaccination

1. A health visitor explains to new parents that their newborn baby is protected against several infections for the first few months of life. The protection comes from antibodies that crossed the placenta from the mother's blood before birth and from antibodies present in her breast milk.
   Explain why the protection from the mother's antibodies lasts only a few months.2 marks
2. A school nurse is reviewing uptake of the MMR vaccine, which protects against measles, mumps and rubella. Measles is highly infectious and about 95% of a population must be immune to prevent outbreaks. In one town, 78% of children have been vaccinated. A small number of pupils cannot be vaccinated because they are receiving chemotherapy.
   Explain how a high level of vaccination in a town would protect the pupils who cannot be vaccinated.2 marks
3. A hiker is bitten by a stray dog in a region where rabies occurs. The rabies virus travels slowly along nerves and can take several weeks to reach the brain, after which the disease is almost always fatal. Doctors give the hiker an injection of human rabies antibodies straight away, followed by a course of rabies vaccine over the next few weeks.
   Explain why the hiker is given both the rabies antibodies and the rabies vaccine.3 marks