Vaccines

• ACTIVE IMMUNITY


  when your immune system makes its own antibodies after being stimulated by an antigen
• Two types of active immunity

  1. Natural = immune after a disease.
  2. Artificial = immune after given a vaccination exposing a harmless dose of antigen
• Passive immunity and two types


  Immunity given by antibodies made by a different organism

  1. Natural = when a baby becomes immune due too antibodies received by mother via placenta or breast milk
  2. Artificial = Becoming immune agter injected with antibodies from somebody else, (could be collected through blood donations)
• Summary of active immunity

  • Required exposure to antigen
  • Takes a while for protection to develop
  • Memory cells produced
  • Protection is long term because antibody is produced in response to complementary antigen present
• Summary of passive immunity

  • No exposure to antigen
  • Immediate protection
  • Memory cells not produced
  • Short term protection as antibodies given are broken down
• Antigens in vaccines causes body to produce memory cells against a pathogen, without pathogen causing disease.
• What do vaccines do

  • Protect individuals, reducing occurrence of disease, those not vaccinated less likely to catch the disease (fewer to catch it from) = herd immunity
• Vaccines

  • Contain antigens, either free or attached to a dead or weakened pathogen
• Disadvantage of vaccines

  • Could be broken down by enzymes in the gut.
  • Molecules of the vaccine too large to be absorbed in the blood
  • Sometime booster vaccines given to reproduce more memory cells.