Vaccination is the centerpiece of preventive care of the well child. Vaccination has been one of the singular public health successes of the past half century, and its full potential remains unrealized. Pneumonia and diarrhea, two of the leading causes of child mortality, account for approximately 1.4 million deaths annually (Liu and others 2016); vaccination with currently available vaccines has the potential to prevent 59 percent of pneumonia-related deaths and 29 percent of diarrhea-related deaths (Fischer Walker, Munos, and Black 2013). Other leading causes of childhood deaths are already preventable through available and effective vaccines, such as measles and meningitis, and other diseases, such as malaria, may become vaccine preventable in the near future (Agnandji and others 2011; Liu and others 2012). Forecasts for vaccine use in the 73 countries supported by Gavi, the Vaccine Alliance, project that 17.7 million deaths will be averted in children under age five years as a result of vaccinations administered from 2011 to 2020 (Lee and others 2013). Childhood vaccination contributed greatly to progress made toward achieving the fourth United Nations Millennium Development Goal, a two-thirds reduction in childhood mortality between 1990 and 2015 (UN 2015), and the centerpiece of several other major