Reasons to immunize your child Vaccines can save your child's life. Here are 7 important reasons to immunize your child. If you choose not to immunize If you choose not to immunize your child, it's important to know the risks and your responsibilities. ABOUT VACCINES How vaccines work Vaccines teach the immune system how to recognize and fight off specific disease-causing germs. Helpful terms Find definitions of the following terms: vaccine, vaccination, and immunization.