The Smith family brought their 2-week-old son into your family practice office for a checkup. They have already expressed multiple concerns to you concerning sleep, feeding, and crying, but their concerns have been about things that are typical for a newborn. You try your best to calm their fears, and they are receptive for the most part. However, when it comes time to discuss vaccination with them, they refuse to vaccinate their son because they have heard vaccines that can cause autism in children. Which of the following statements is not true concerning vaccines?
a. they consist of killed or inactivated cells
b. they consist of live but weakened microbes
c. it is possible to be allergic to vaccine preparations
d. autism only happens in rare instances because of vaccination