All children should be immunized at regular health care visits, beginning at birth. Immunizations are very important in keeping children healthy. The recommended childhood and adolescent schedule urges vaccinations starting at birth through 24 months of age, with boosters and catch-up vaccines continuing through the teenage years and into adulthood. By immunizing, children are protected against the potentially devastating effects of vaccine-preventable diseases. Immunization is the most cost-effective preventive health measure.