Good health is an essential determinant of social development and economic growth.
Currently used vaccines, vaccines available but not yet widely used in the developing countries, and vaccines expected to be available within the next few years can potentially reduce excess mortality by as much as 3.5 million, or more than a quarter of the excess mortality. Immunization services disproportionately benefit the poor and vulnerable populations, provided they reach them, and are one of the most important and cost-effective interventions that a health system can provide. Coverage of immunization services, which is relatively easy to measure, is also a useful indicator of access by the poor to basic social services. The World Health Assembly and the World Summit for Children have called for specific targets for the immunization services to reduce the excess mortality and disability. However, children's access to immunization services varies significantly by region.