Vaccination
Immunization is when a person's immune system learns to fight an infection. Immunization can happen from vaccination. But immunization can also happen from getting the infection. For example, a person can be immune to hepatitis B if he gets sick with hepatitis B. After a person gets hepatitis B and then gets well, he is immunized from getting it again. A person can also be immunized from hepatitis B by taking the hepatitis B vaccination.