Immunity

Active Immunity

• Active immunity occurs when the body produces its own antibodies.
• This gives long term immunity because memory cells survive in the body.
  • There are two types of active immunity:
  1. Natural active immunity
  2. Artificial active immunity

1. Natural Active Immunity:

• Occurs when a pathogen enters the body in a normal/natural way.
• Example: Chicken pox.

2. Artificial Active Immunity:

• Involves injecting or ingesting small doses of non-reproductive antigens (e.g., parts of a pathogen).
• This stimulates antibody production without causing illness.
• This method is known as vaccination or immunisation.
• Examples: TB (BCG injection), polio, meningitis, and MMR (measles, mumps, rubella).

Passive Immunity

• Passive induced immunity occurs when antibodies pass from one organism to another.
• It provides short-term immunity because antibodies last only about 6 months and no memory cells are produced.
• There are two types of passive immunity:
  1. Natural passive immunity
  2. Artificial passive immunity

1. Natural Passive Immunity:

• Antibodies pass from a mother to her child.
• This can take place in the womb via the placenta or during breastfeeding.
• Babies do not normally suffer from common infections for the first 6 months of their lives due to the antibodies received from their mothers.
• Breastfeeding extends the period of immunity.

2. Artificial Passive Immunity:

• Involves injecting antibodies into a person to counteract a specific disease.
• Example: Tetanus injection.