Vaccinations

• What is passive immunity?

  • Introduction of antibodies from an outside source
  • No direct contact with the pathogen or its antigen
  • Immunity is acquired immediately
  • No memory cells formed so no lasting immunity
• What is active immunity?

  • Produced by stimulating the production of antibodies by the individuals own immune system
  • Direct contact with the pathogen or its antigen
  • Immunity takes time to develop
  • Long-lasting
• What are the 2 types of active immunity?

  • Natural active immunity
  • Artificial active immunity
• What is natural passive immunity?

  • Individual is infected by the disease under normal circumstances
  • The body produces its own antibodies
• What is artificial active immunity?

  • Immunity acquired through vaccination
  • Includes immune response without them suffering from the symptoms of the disease
• Features of a successful vaccination programme?

  • Vaccinations economically available in sufficient amounts to vaccinate most vulnerable populations
  • Few side effects - To encourage people to be vaccinated
• Describe Herd immunity

  When a large proportion of the population has been vaccinated making it difficult for a pathogen to spread within that population
• Why might vaccination not eliminate disease?

  • Vaccination did not induce immunity in some individuals
  • May develop disease immediately after the vaccination but before the immunity levels are high enough to prevent it
  • Pathogens may mutate frequently so the antigens change suddenly (antigenic variability)
• Ethical issues with vaccinations

  • Animal abuse
  • Vaccines have side effects than can cause long-term harm
  • How vaccines are tested and how trials are carried out
• Describe how vaccination can lead to protection against bacterial meningitis (6 marks)

  • Antigen on bacterial meningitis binds to the surface protein on a B-cell
  • B-cells divide by mitosis and produces clones
  • This is stimulated by cytokines
  • Plasma cells release antibodies
  • Some release memory cells
  • Memory cells produce antibodies faster