Vaccination against serious and life-threatening infectious diseases in children is one of the greatest achievements of public health. Since the 1970s, global immunization programs have saved approximately 154 million lives. In countries with strong vaccination programs, diseases that once filled hospital wards and killed many children have largely disappeared. The US immunization program has been supported by consistent scientific recommendations from the Advisory Committee on Immunization Practices (ACIP) since 1964. These evidence-based recommendations have contributed to improving children's health.[1]