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Vaccines: The Basics

Vaccines contain the same germs that cause disease. (For example, measles vaccine contains measles virus, and Hib vaccine contains Hib bacteria.) But they have been either killed or weakened to the point that they don't make you sick. Some vaccines contain only a part of the disease germ.

A vaccine stimulates your immune system to produce antibodies, exactly like it would if you were exposed to the disease. After getting vaccinated, you develop immunity to that disease, without having to get the disease first.

This is what makes vaccines such powerful medicine. Unlike most medicines, which treat or cure diseases, vaccines prevent them.

For more than the basics, see:

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