The goal of
immunization is to prevent disease. Immunization can happen from
vaccination and also can happen from getting the infection. For example, a person
can be immune to hepatitis B if he gets sick with the disease
and gets better. He is
immunized from getting it again. Until a disease has
disappeared, it remains a risk to unimmunized people. A person can also be immunized
from hepatitis B by taking the hepatitis B vaccination.
If we stop immunization against diseases that are still circulating,
it will infect the unimmunized and which in turn, will spread to
others, leading to outbreaks, or epidemics.