sentence: Immunization is when a persons immune system learns to fight an infection.
sentences_after: Immunization can happen from vaccination. But immunization can also happen from getting the 'infection'. After a person gets hepatitis B and then gets well, he is immunized from getting it again. A person can also be immunized from to hepatitis B by taking the hepatitis B vaccination.
concept_name: immunization
headings: Vaccination Vaccination versus Immunization
categories: Immunization