5.6 vaccination

• immunity is the ability of an organism to resist infection
• passive immunity is produced by the introduction of antibodies into individuals from an outside source
• passive immunity:

  1. direct contact with the pathogen isn't necessary
  2. immunity is acquired immediately
  3. immunity doesn't last
• active immunity is produced by stimulating the production of antibodies by the individuals own immune system
• active immunity:

  1. direct contact with the pathogen is necessary
  2. immunity takes time to be acquired
  3. immunity does last
• two types of active immunity:

  1. natural active immunity
  2. artificial active immunity
• natural active immunity results from an individual becoming infected with a disease under normal circumstances and produces its own antibodies
• artificial active immunity involves inducing an immune response without the individual suffering the symptoms of the disease
• herd immunity arises with a sufficiently large proportion of the population has been vaccinated to make it difficult for a pathogen to spread