Before vaccines, many children died of diseases vaccines now prevent, such as whooping cough, measles, and polio. Those same germs exist today, but babies are now protected by vaccines, so we do not see these diseases as often. Immunizing individual children also helps to protect the health of our community, especially those people who are not immunized. Also protected, therefore, are people who received a vaccine, but who have not developed immunity. In addition, people who are sick will be less likely to be exposed to disease germs that can be passed around by unvaccinated children.
Immunization also slows down or stops disease outbreaks.