Explain how vaccination makes a person immune to a disease

Answer:A dead or inactive or weak form of pathogen is introduced. (Don't say Germ)This stimulates white cells / lymphocytes / leucocytes - B and T cells (not phagocytes)to produce antibodies. Antibodies are produced quickly after re-infection (by B cells). Fun fact: The MMR vaccine (Measles, Mumps and Rubella) is a live (but attenuated- harmless) version of the viruses.