Vaccination (Cambridge (CIE) IGCSE Biology): Revision Note

Vaccination: Extended

Extended Tier Only

• Vaccinations give protection against specific diseases and boost the body’s defence against infection from pathogens without the need to be exposed to dangerous diseases that can lead to death

• The level of protection in a population depends on the proportion of people vaccinated (opens in a new tab)

• Vaccines allow a dead or altered form of the disease-causing pathogen, which contains specific antigens, to be introduced into the body

• In this weakened state, the pathogen cannot cause illness but can provoke an immune response

• Lymphocytes produce complementary antibodies for the antigens

• The antibodies target the antigen and attach themselves to it in order to create memory cells

• The memory cells remain in the blood and will quickly respond to the antigen if it is encountered again in an infection by a ‘live’ pathogen

• As memory cells have been produced, this immunity is long-lasting