Vaccine-preventable disease levels are at or near record lows. Even though most infants and toddlers have received all recommended vaccines by age 2, many under-immunized children remain, leaving the potential for outbreaks of disease. Many adolescents and adults are under-immunized as well, missing opportunities to protect themselves against diseases such as Hepatitis B, influenza, and pneumococcal disease. CDC works closely with public health agencies and private partners to improve and sustain immunization coverage and to monitor the safety of vaccines so that this public health success story can be maintained and expanded in the century to come. Click the links below to find out more.