National Infant Immunization Week (NIIW) is April 18–25, 2015. This annual observance promotes the benefits of childhood immunizations and their role in improving the health of children aged ?2 years. Since 1994, local and state health departments, immunization partners, health care professionals, community leaders, clinicians from across the United States, and CDC have come together to highlight the importance of vaccination in the lives of infants and children.