Shots may hurt a little, but the diseases they can prevent are a
lot worse. Some are even life-threatening. Immunization shots,
or vaccinations, are essential. They protect against things like
measles, mumps, rubella, hepatitis B, polio, diphtheria,
tetanus, and pertussis (whooping cough). Immunizations are
important for adults as well as children. Your immune system
helps your body fight germs by producing substances to combat
them. Once it does, the immune system "remembers" the germ and
can fight it again. Vaccines contain germs that have been killed
or weakened. When given to a healthy person, the vaccine
triggers the immune system to respond and thus build immunity.
Before vaccines, people became immune only by actually getting a
disease and surviving it. Immunizations are an easier and less
risky way to become immune. NIH: National Institute of Allergy
and Infectious Diseases References and abstracts from
MEDLINE/PubMed (National Library of Medicine)