This chapter presents a social scientific perspective on vaccines, showing how to think of vaccines as thoroughly social and political, that is, created through law, regulation, political will, and ideologies as well as through scientific development. This chapter explains how vaccines are approved and recommended, what the current recommended vaccine schedule for children in the United States looks like, and how it has changed over time and examines the state-level politics of school entry immunization requirements. It also describes the structure of our federal vaccine safety monitoring system, underscoring how federalism and our lack of a comprehensive national health care system create difficulties in detecting vaccine injuries.